rt tae saLeReD Oe ALBERT R. MANN LIBRARY AT CORNELL UNIVERSITY Cornell University Library The Bacteria. “ruin Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924003200288 THE BACTERIA. BY DR. ANTOINE MAGNIN, LICENCIATE OF NATURAL SCIENCES, CHIEF OF THE PRACTICAL LABORS IN NATURAL HISTORY TO THE FACULTY OF MEDICINE OF LYONS, LAUREATE OF THE FACULTY OF MEDICINE OF PARIS (SILVER MEDAL, 1876), GENERAL SECRETARY OF THE BOTANICAL SOCIETY OF LYONS, MEMBER OF THE BOTANICAL SOCIETY OF FRANCE, ETO. TRANSLATED BY GEORGE M. STERNBERG, M.D., SURGEON U. s. ARMY. BOSTON: LITTLE, BROWN, AND COMPANY. 1880. Copyright, 1880, By Georce M. STERNBERG. UNIVERSITY PREss: Jonn Witson AND Son, CAMBRIDGE. PREFACE BY TRANSLATOR. Havine found the admirable reswmé of our knowl- edge of the bacteria, by Dr. Magnin, of great assistance to me, in pursuing the investigations in which I have been engaged during the past year under the auspices of the National Board of Health, it has seemed to me that a translation of the work into English and its publi- cation in this country would be productive of good in more ways than one, and of the advancement of science. To the naturalist, it cannot fail to be of value, as the most approved classification, that of Cohn, is given, with a full description of species. To give additional value to this portion of the work, figures of many of the best-known forms, drawn from various foreign sources, and reproductions of some of my own photo-mico- graphs (by permission of the National Board of Health), have been introduced. If we are to judge from the scanty literature of the subject in this country, the amount of interest which has been aroused by the revelation of a new world of micro-organisms, and by the momentous questions which have been raised in connection with them, is far below that awakened in Germany, France, and England. This is not, however, really the case ; for, while we have but few active workers in the difficult fields of inquiry 4 PREFACE BY TRANSLATOR. which have proved so attractive, especially for the Ger- man and the French savants, there is nevertheless a wide-spread interest in these investigations, and a desire to know their results. But, just here, we are met with a difficulty which has no doubt discouraged many, and perhaps caused some to drop the whole subject in dis- gust. The results have been so contradictory, and so many would-be savants have uttered opinions entirely opposed the one to the other, that we find it impossible to arrive at any definite opinion, not knowing whom to believe. This being the condition of affairs, it seems to me that it is necessary for us to commence investigating for ourselves, — first making ourselves familiar with what has been done abroad, and then avoiding, if possible, the quicksands into which unfortunate science has too often been dragged by her votaries. One great trouble which we have experienced in this country is in judg- ing of the comparative value of the observations of dif- ferent men who are equally unknown to us. A very plausible article may be written by a very careless observer; or a very cautious observer may fail to give confidence in his results, because of a certain degree of confusion in his language. When experiments are well devised, carefully executed, and described with preci- sion, as is done by such men as Pasteur and Tyndall, we cannot fail to attach great weight to the conclusions reached. And when so accomplished a microscopist as Cohn or Koch asserts that he has seen such and sucha thing, or has made such and such measurements, we cannot doubt the reliability of the observation. But sometimes we are deceived by giving credence to a man who has achieved reputation in one line of study, but of PREFACE BY TRANSLATOR. 3) whose skill and training in the use of the microscope we have no means of judging. Such a man may be a great surgeon, or a great clinician, or a great chemist, and yet be a mere tyro with the microscope. When, then, we see it announced that Dr. So-and-so failed to discover any mterococci in pus, in blood, or what not, taken from a certain source, we are justified in asking, — first, what power did the learned doctor use? second, is he capa- ble of distinguishing micrococci in fluids which contain them beyond question? Or, if he does discover them, we may ask if he is accustomed to making a differential diagnosis between micrococci and inorganic granular material, or unorganized granules of organic origin. This is a decision which the most accomplished micro- scopist is sometimes unable to make, except by the aid of chemical tests and culture experiments. To avoid this want of confidence in results, which has naturally grown out of carelessly made observations and contradictory statements, it is desirable that full and minute details should be given of all observations and experiments made, and, whenever possible, that photo- micographs should be made of all micro-organisms described, or of a thin stratum of a liquid asserted not to contain any; as, when a sufficiently high power is used, this settles the question of their presence or absence, beyond dispute, and enables other students to make comparisons and measurements which cannot fail to promote the interests of true science. The National Board of Health of the United States has the credit of first adopting this method of recording the results of scientific investigation, in this direction, as a constant and unimpeachable record of what has 6 PREFACE BY TRANSLATOR. been seen by the investigator. The commission sent to Havana last summer for the investigation of yellow- fever, was instructed to pursue this method, and was accompanied by a photographer and supplied with all the necessary appliances for carrying these instructions into effect. The superficial reader may find much to criticise in the work of Dr. Magnin, but I am convinced that those who read it carefully cannot fail to be pleased with the truly scientific spirit in which it is written; the fairness with which conflicting opinions are stated ; the caution manifested as to the drawing of definite conclusions where questions are still under discussion ; and, above all, the extent of his literary researches and the systematic way in which he has arranged the re- sults. For the naturalist, for the physician, or for the non- professional man of general culture, who desires to have accessible in a condensed form the most important re- sults achieved in this line of inquiry up to the present day, this volume cannot fail to be of value; while for the student and the investigator in search of fuller information, the summary given of the labors of nu- merous individuals, together with the copious bibliog- raphy, which I have brought up to date, will doubtless be of service. Believing this to be true, it has been a pleasure for me to devote a portion of my summer vaca- tion to the translation of this little volume. G. M.S. Satem, Mass., August 1, 1880. TABLE OF CONTENTS. PAGE INTRODUCTION. . . 2. ee ee ee ew we we ee UCD HISTORICAL, 4. -% “Hoos Seba ow SE Bde Ww we woe. 28 PART FIRST. MORPHOLOGY OF THE BACTERIA. CHAPTER I.— OrcanizaTIon. § 1.—OrF THe BacTERIA IN GENERAL. . . . . . . 98 Forms 4 < 5 ¢ # | Ss #8 6 wo ae ww (98 Dimensions a6. 6 ae we a we ee we OD Corgis 3 Bens. Se! Sel aw Ms) a St ee eee SL Movements . ........2.4. 2.2. 82 Structiire:. 2 2 eee ee we we ee BS Cell-Membrane. . . . . .... O85 Protoplaam . . . 1... 1... es . 86 Gillie sey, aic'g Sy. Wy BE dor gie ck EE Bin wet el 889 § 2.—DirrrrentT MopEs or AssocraTION. . . . . . 48 Form of Little Chain ae: @icee ty a Bo 48 Form of Zooglea . . . o 8 aoe ww oy ORE Form of Mycoderma, &e. . . . . . . . . 46 CHAPTER II.— CrassiFicaTion AND DESCRIPTION. § 1.—Puacre or THE BacTERIA . ....... . 48 Among Organized Beings . . . . ... . 658 In the Vegetable Kingdom . . . . . . «. . 55 § 2.— CLASSIFICATION. . . Stee We a Bee IBY Characters Generic atta Spseific ica So aoe 760 Classification of Cohn. . . . . ... . «~~ 65 8 TABLE OF CONTENTS. § 8.—DescripTION OF GENERA AND SPECIES . . . - 65 Spherobacteria . 2. 1 1 ew ew ee ee OTD Micrococcus . . 6 1 1 ew ee ee we ee TD Monads ay 4 4 Sw Bae we ee a Microbacteria . . 2... ee ee ee e880 Bacterium. . 2. 6. 6 2 6 we ee we we ee) (8D Desmobacteria . . 2... 2 eee ee (86 Bacillus jee eR OE ae we ey BT Leplothrite. 08 a ae ee es we 80 Spirobacteria . 2. 1. 2 1. ee ee ee) OL Vado: a Gr ep Sabie. Sgn Ca BA IQS AS Ae a) Che ee B82 Spirilum 5 6 4 ee 4 ee ee ew OF PART SECOND. PHYSIOLOGY OF THE BACTERIA. CHAPTER I.— DEVELOPMENT IN GENERAL. g 1.—Oricin or Bacteria. . . . . .. . . . - 101 Heterogenesis . . . . . - «. «. «© « © « 102 Dissemination . . . 2... 1 we ew se «(108 TipAGi oe: 38 osu. SES Soe ae, Gh Se ae ee te OB Tn Water. Gl ew en AP ee a we ee ee 106 In the Human Organism. . . . . . . . . 107 § 2.— Nutrition AnD RESPIRATION. . . ... .. Ill Alimenitsis Wate® 2. 5. 4 2 2 & ae e 4 « TUL Nitrogen « 2 4 2 8 2% % # « 112 Carbon; « «© « # « + @ « » « 118 OXYGEN se ei ae ee ee, Ba BB Temperature. . . . . 2... . ~~ 118 Other Agents . . . . . . ...... 121 § 3.— REPRODUCTION . . . . 1... ew ee ee 198 Fission. .2 ¢ @ 4.08 2 & ew tue « @ 198 POPES: 2 kee ee a a Re a GS. es HG Sporangia. a se 2 8 woke ww @ 180 Polymorphism . . . . . 2 ee. 1 1. . 188 TABLE OF CONTENTS. 9 CHAPTER II.—DeEveEtopmMent IN DiFFERENT MEDIA. PAGE § 1.—Ré.e or Bacrerta iN FERMENTATIONS . . . . 187 Acetic Fermentation . . . . ... . . . 189 Ammoniacal Fermentation. . . . . . . . 142 Lactic and Butyric Fermentation. . . . . . 144 § 2.—R6Le vn PurReracTION AND NITRIFICATION . . 148 § 8. —R6LE In VirULENT AFFECTIONS . . . . . - « 152 Septicemia 2. 6. 6. 6 6 1 ee ee ww we 152 Charbon~ <0 «kg eS) Ge Be Se) Ge ow ES Wariolay 8 aa Sse at Se me ae ee ALOT Searlating . . 2. 1 1 6 6 ee ew ew ew «(169 Measles 2 6 8 6 ee & we ® % % « = 169 Diphtheria 2. . 1. 1 1. ww ew ew ee ee 6170 Typhoid Fever . . . 2... ew ew ee 6171 Glanders, Farcy . . . 2. ee ee ee 171 Endocarditis. . 2. 2. 2. ee es ee we 178 § 4.—RéLe ry Surcicat Lesions . . . - se e+ 1% Exposed tothe Air. . . . 2. « » + « « 176 Closed) 0k ws, Je 8) owe a eS Therapeutic Deductions . . . « - « « ~ « 185 ConciUSIONS: = « 6 6 s * 6 me ee w 2 ew « » 188 BIBLIOGRAPHY. . . . we ee wee ee ew we (191 INDEX! Se! gh tntte BPR! leaned Be yeas het Ge Lae 228 PLATE VIII. LIST OF PLATES. OPPOSITE PAGE The Cilia of B. termo and S. voluntans. (Drysdale and Dallinger) . . . . . 2. 2 ee we) 40 Different Modes of Grouping of the Bacteria . . . 47 Saccharomycétes and Schizomycétes . . . . . . 58 Disease Ferments of Wort and Beer. (Pasteur). . 84 Different Forms of Bacteria. (Cohn) . . . . . 95 Different Forms of Bacteria. (From Photo-micro- graphs by Dr. Sternberg) . . . . . . . . .) 98 Dissemination of the Bacteria. (From Photo-micro- graphs by Dr. Sternberg) . . . . . . «. . . 100 Reproduction of Bacillus Uina, by Spores. (Photo- micrographs by Dr. Sternberg) . . . . . . . 127 Formation of Spores in Bacillus, &&. (Koch). . . 153 Spirillum Obermineri and Bacillus Anthracis. (Koch). 268 THE BACTERIA. INTRODUCTION. ‘¢Corruptio unius est generatio alterius.”’ Lucretius, De Rerum Natura. Or all the studies which have for their object the inferior organisms, those which relate to the bacteria offer, without contradiction, the greatest interest, as they touch the most divers problems, which, it is true, are the most difficult and the least known in biology. The history of these mi- nute organisms is, in truth, related to that of spontaneous generation, to that of the fermenta- tions, to the pathogeny and therapeutics of a great number of virulent and contagious affections, and, in a more general manner, to all the unknown which, notwithstanding the efforts of modern sci- ence, still surrounds the origin of life and its pres- ervation. If the relation of these inferior organisms to the origin of living beings is yet obscure, their role in the preservation of life is better known. It is known that organic matter, once produced and become solid, so to speak, cannot again enter into the general current until it has undergone 12 THE BACTERIA. new transformations, metamorphoses produced, ac- cording to some savants, favored, according to others, but, without contradiction, accompanied by the development of bacteria;' and, without wishing to attribute to these organisms a finality which is repugnant to our monistic conception of the universe, it may be said that it is thanks to them that the continuation of life is possible on the surface of the globe. But, if these studies are full of interest, their field is so vast that we cannot flatter ourselves that we have passed over the whole of it with equal care. The little time that has been ac- corded us for the composition of this thesis will be our excuse for the inevitable imperfections which will doubtless be found in our work. 1 The bacteria: such is the subject which has been imposed upon us; but it is certainly useless to give the reasons which have caused us to study not only the bacteria properly so called, taking the word in its most restricted sense, but all the organisms which are comprised under the names of bacteria, vibrios, schizomycétes, schizophytes, etc. HISTORICAL. Tue bacteria are the lowest organisms, situated upon the limit of the two kingdoms, animal and vegetable, and are thus defined by the botanists who have most recently occupied themselves with them : — “ Cells deprived of chlorophyll, of globular, ob- long, or cylindrical form, sometimes sinuous and twisted, reproducing themselves exclusively by transverse division,’ living isolated or in cellular families, and having affinities which approach them to the algex and especially to the oscillatoriz.” But, before arriving at this degree of relative precision, the history of the bacteria has passed through the most diverse vicissitudes. At one time considered as animals, at another taken for vegetables, transported from the alge to the fungi, one author has even gone so far as to refuse to them the nature of living beings.” This diversity of opinions is due to the minuteness of their di- mensions and the difficulties with which their ob- servation is surrounded. 1 Reproduction by spores has been proved to occur in Bacillus subtilis, and it seems altogether probable that other species are reproduced in the same way.—G. M.S. 2 Polotebuow. 14 THE BACTERIA. Although an historical statement of the progress of our knowledge of these minute organisms has been given in several publications, we think it best to make here a new historical summary, which will be completed by an indication of the principal pa- pers relating to them which have been published recently. The first observer who perceived bacteria .was Leeuwenhoeck. As early as 1675, while examin- ing by chance with his magnifying glasses a drop of putrid water, the father of microscopy re- marked with profound astonishment that it con- tained a multitude of little globules, which moved with agility. The following year he recognized the presence of bacteria in feces and in tartar from the teeth; and, if he has not named them, it is easy to assure one’s self by the description which he has given of their form and of their movements, and by the figures which accompany these descriptions,’ that the organisms observed by him are truly Bacteria, Vibrios, and perhaps even Leptothriz. In 1773 O. F. Miiller endeavored to classify these organisms. He made of them a group of infusoria, under the name of Jnfusoria crassius- cula, and established two genera, —the g. Monas and Vibrio; the first characterized as follows: “vermis inconspicuus, simplicissimus, pellucidus, punctiformis,’ comprising the following species: Monas termo, atomus, punctum, ocellus, lens, mica, } Leeuwenhoeck. Opera omnia, Lugd. Batav., 1722, 11, p. 40, fig. A to G. HISTORICAL. 15 tranquilla, lamellula, pulvisculus, wva, which it is impossible to identify with the species at pres- ent recognized. The genus Vibrio “ vermis incon- spicuus, simplicissimus, teres, elongatus,” enclosing under thirty-five specific names, with the true bacteria, some organisms belonging to other classes of the animal and vegetable kingdoms. In the classification of the infusoria given by- Bory de Saint-Vincent in the “ Encyclopédie Méthodique” (1824) and afterwards in the “ Dic- tionaire Classique d’Histoire Naturelle” (1830) the bacteria are distributed in two different families of the microscopic gymnodex, the monadaires and the vibrionides. Besides the monads, properly so called, of which the Monas termo has been pre- served by the greater part of the bacterologists, the monadaires include some veritable infusoria, which have no relation with the monads. It was the same with the vibrionides, of which the genera Vibrio and Mellanella included some beings very different in their organization. Indeed, beside some veritable vibrios, bacteria, and spirilla, constituting the genus Mellanella, Bory placed some nematoid worms, such as the Anguillula of vinegar. With Ehrenberg (1838) and Dujardin (1841) the family of the vibrioniens was established upon characters more homogeneous, and their species upon distinctions truly scientific. But these two observers, followed in this by M. Davaine, deny completely the affinities of the elongated bacteria 16 THE BACTERIA. (Bacterium, Vibrio, etc.) with the punctiform bacteria (Jonas); and it is necessary to come to the time of MM. Hallier, Hoffmann, Cohn, and the greater number of recent botanists, in order to see these two forms brought together anew. In fact, Ehrenberg defines his vibrioniens, which he arranges between the volvocinee and the closteria “animals, filiform, distinctly or appar- ently polygastric, no mucous membrane, naked, without external organs, with the body (like mon- ads) uniform and united in chains or filiform se- ries, as a result of incomplete division.” He included in this class: all filiform bodies gifted with proper movement and formed of articles, dividing them into four genera :— 1. Bacterium: filaments linear and inflexible; three species. 2. Vibrio: filaments linear, snakelike, flexible; nine species. 3. Spirillum: filaments spiral, inflexible; three spe cies. 4. Spirochete: filaments spiral, flexible; one species. A fifth genus, including but one species, the Spirodiscus fulvus, with filaments in a helix, in- flexible, disposed in contiguous layers, has not been seen since Ehrenberg. Let us add that Ehrenberg often attributed to them a complex structure, stomachs more or less numerous, a pro- boscis, cilia serving as organs of locomotion, — all characters that more recent observers have failed to find. Nevertheless, we must make an HISTORICAL. 17 exception in favor of the cilia, of which the ex- istence has been recently verified in the case of several of the bacteria by divers botanists, among others by MM. Cohn and Eug. Warming. Dujardin (1841), in his “ Histoire Naturelle des Zoophytes,” preserved the family of the vibrioni- ens of Ehrenberg among the infusoria, characteriz- ing them as follows: “ filiform animals, extremely slender, without appreciable organization, without visible locomotive organs.” He made but few modifications, of which the principal consisted in uniting Spirocheta with Spirillum, Dujardin. Re- jecting the character that Ehrenberg drew from the rigidity of the spirilla, the Spirocheta plica- tilis, Ehrb. became the Spirillum plicatile, Duj. ; but, as will be seen later, this change has not been maintained. Dujardin, then, classed the bac- teria in: 1. Bacterium: filaments rigid, with a vacillating movement. 2. Vibrio: filaments flexible, with an undulatory movement. 3. Spirillum: filaments spiral, movement rotary. Until this time the bacteria had been considered as animals placed at the foot of the series. Sub- sequently the tendency to place them in the vegetable kingdom became more and more pro- nounced. Already, since 1853, M. Ch. Robin had pointed out the relationship of the bacteria and of the 2 18 THE BACTERIA. vibrios with Leptothrix. This opinion, which was not favorably received by the authors who adopted nearly all of the generic groups of Ehren- berg and Dujardin, is to-day accepted by many botanists, above all since the labors of Cohn. (See below: classification.) At all events, it is to M. Davaine (1859) that we are indebted for clearly pointing out that the vibrioniens are vegetables, nearly allied to the algx, and especially to the conferve. This same author, having observed some mo- tionless bacteria, thought it necessary to give this character great consideration, and to estab- lish a fourth group, the genus Bacteridium, which he added to the three others admitted by Dujar- din; but in this creation he was less happy than in his placing the vibrioniens among the vege- tables; for we shall see further on that this char- acter of mobility or of immobility is not absolute, and that it depends upon the age of the bacterium or upon certain conditions relating to the medium in which it is placed. The most recent complete exposition of the classification and of the ideas of M. Davaine is found in the “ Dictionnaire Encyclop. des Sci- ences Médicales,” art. Bactéries (1868). It may be summed up as follows: — or bent, but not neously . .§ Flexible. Vuisrio. in a spiral Motionless . . . . . BactTERipium. Filaments spiral . . . . . . . . . . SPIRILLUM. Filaments straight | Moving ae Rigid. . Bacterium. HISTORICAL. 19 The genus Bacterium comprises six species, — B. termo, catenula, punctum, triloculare, or articula- tum, already described by Ehrenberg and Dujar- din, and B. putredinis and capitatum, new species of M. Davaine, established, the first for a bacte- rium producing rot in plants, the second for a spe- cies, swollen at the extremity, observed in some macerations. The genus Vibrio includes twelve species, — V. lineola, tremulans, rugula, prolifer, serpens, bacillus, synxanthus, and syncyanus of previous authors and the V. lactic, butyric, and tartaric right, discovered by M. Pasteur in these different fermentations. In the genus Bacteridium, M. Davaine places five new species,—the “ Bactéridies charbonneuse, intestinale, du levain, glaireuse, et des infusions.” He includes also the ferment which, according to M. Pasteur, occasions the “sickness of turned wine.” Finally, the genus Spirillum includes the spe- cies S. undula, tenue, volutans of Ehrenberg, S. rufum and leucomenum of Perty, and S. plicatile, Duj. From this moment the history of the bacteria enters upon a new phase. The labors of M. Pas- teur upon the inferior organisms and their réle in fermentation, the researches of MM. Davaine and Hallier upon the bacterium of charbon, and the micrococci of contagious maladies, call the atten- tion of chemists and of pathologists to these or- 20 THE BACTERIA. -ganisms and especially to the bacteria. Their origin, their evolution, the physiological peculi- arities of their nutrition and reproduction, are the object of numerous labors, and give rise to passionate discussions relating to the subject of spontaneous generation, polymorphism of fungi, theories of fermentation, and the pathology of virulent and infectious maladies. For this reason an exposition of these researches, often contradic- tory, is extremely difficult. We will make it suc- cinctly, insisting especially upon the labors relating to the classification of the bacteria, and reserving to ourselves the privilege of returning to the his- tory of several points, when we approach their study in the special chapters of this thesis. The first important memoir published after that of M. Davaine upon the bacteria is that of M. Hoffmann, in 1869. He demonstrates: First, that the bacteria are plants, having a very distinct cellular organization; second, that they can only be classified in accordance with their form and size, at first into monads and linear bacteria, and the latter into microbacteria, mesobacteria, and megabacteria; (M. Hoffmann includes with the linear bacteria, Vibrio, Bacterium, and Leptothriz, which are bacteria united in a chaplet;) third, that mobility or immobility is not a specific char- acter, but may present itself in the same species under the influence of changes of temperature, of density of medium, etc. M. Hoffmann studies also the origin of the bacteria, and rejects the hypothesis of a spontaneous generation. As to HISTORICAL. 21 their réle in the phenomena of the decomposition of organic bodies and in fermentations, M. Hoff- mann confesses “ that, with the exception of yeast. and of the acetic and butyric ferments, all the rest is still enveloped in obscurity.” M. Cohn is the naturalist who, in our days, has occupied himself the most with the bacteria. In 1853, he published his first researches upon this subject. The genera Zooglea, which he estab- lished at this time for the bacteria arranged in ge- latinous masses, diffused or more or less crowded together, was not a happy creation. It was adopt- ed at first by M. Rabenhorst who, in his work on the fresh-water algze of Europe, places them after the palmellacese, while he classes the other bac- teria, Vibrio and Spirillum, in the family of the oscillatoriz. The Zooglea are later abandoned by their author as a generic group, and are preserved only as the name of one of the diverse transitory stages through which the bacteria pass in the course of their evolution (Zooglea, Leptothriz, Torula). Twenty years later the same savant commenced the publication of a series of “Memoirs” upon these organisms (in his “ Beitrage zur Biologie der Pflanzen”). In the first paper the author gives an exposition of his researches upon the organization, development, and classification of the bacteria, and upon their action as ferments. M. Cohn considers them as a well-defined group, — the schizospores, belonging to the alge, at the commencement of the series of the phycochroma- 22 THE BACTERIA. cee, with several families with which the different genera of bacteria have many affinities. He rec- ognized, however, that the absence of chlorophyll approaches them, at least from a functional point of view, to the fungi. Upon this point we may say that for other botanists this character is de- cisive, and the bacteria are classed as fungi. ‘ M. Nageli, who takes this view, describes them under the name of Schizomycetes. Cohn divides the bacteria into four tribes, comprising six genera: — 1. The Spherobacteria or globular B. 2. The Microbacteria or rod B. 8. The Desmobacteria or filamentous B. 4, The Spirobacteria or Spiral B. We will return to this classification. In 1874, M. Th. Billroth, in his researches upon the Coccobacteria septica, expressed opinions en- tirely different from those of Cohn. According to Billroth, the bacteria differ considerably in form according to the medium in which they are placed and divers circumstances. He claims that they constitute but a single species, the Coccobac- teria septica. This vegetable organism can pre- sent itself under the form of globular articles (coccos) or under that of rods (bactérie). These two forms may reproduce themselves by becoming elongated and dividing transversely, or may pass the one into the other. Billroth claims to have found both forms united in a single filament, a HISTORICAL. 23 fact which in his opinion demonstrates conclu- sively their relationship. Each of these two forms can also present variations of size, in ac- cordance with which he establishes the following divisions : — Micrococcos. . . . . . « Microbacteria. Mesococcos . . . . . «. «. Mesobacteria. Megacoccos. . . . . . . Megabacteria. And varieties of association which give rise to the following names : — Monococcos. . . . . ~. Monobacteria. Diplococcos . . . . . . + Diplobacteria. Streptococcos . . . . . Streptobacteria. Gliacoccos . . . . . . #£Gliabacteria. Petalococcos . . . . . Petalobacteria. Ascoccos. The following year (1875), Cohn, in the second part of his “ Researches’ upon the bacteria, criti- cised the opinions expressed by Billroth in the pre- ceding memoir. Cohn believes that we should regard as distinct genera and species all the bac- teria having a particular form and acting differ- ently as ferments, so long as the proof of their identity has not been demonstrated in an evident manner. Coming back also to the affinities and classification of these organisms, he insists anew upon their near relationship to the Phycochro- maces; and, no longer distinguishing the bac- teria as a special family, he distributes his different genera in a group, which he calls Schi- zophytes, which includes the greater part of the 24 THE BACTERIA. Chrococcee and of the Oscillarie. We will re- turn to this subject when we speak of the clas- sification of the bacteria. In 1876, appeared in the same number of Cohn’s “ Beitrage” two important papers. The first, by Cohn, treats of the influence of tempera- ture upon the bacteria, of their origin, of the formation of spores in the Bacillus of hay infu- sion, and of charbon. The second, by Koch, gives the result of his researches upon the bac- teria of charbon, the Bacillus anthracis. Koch has been able by skilful cultivation to follow the complete development of this Bacillus, and to witness the formation of spores, of which the vitality is very great, and which are the prin- cipal agents of the transmission of this terrible malady. I must still indicate, in addition to these special works, a quantity of notes and of memoirs scat- tered through the reviews and periodical publica- tions. The list will be found in the bibliography ap- pended to this work. I must also cite the recent work of M. Nageli upon “The Inferior Fungi and their #6éle in Infectious Maladies.’ The learned professor of Munich has studied the di- verse fungi which produce decompositions. He divides them into three groups,—the Mucorini, the Saccharomycetes, and the Schyzomicetes, which correspond to the bacteria. According to Nageli, HISTORICAL. 25 the ‘bacteria are fungi which produce putrefac- tion. In presence of these opinions, so diverse, as to the nature of the bacteria and their classification, we will finish by saying with Cohn: — “So long as the makers of microscopes do not place at our disposal much higher powers, and, as far as possible, without immersion, we will find ourselves, in the domain of the bacteria, in the situation of a traveller who wanders in an un- known country at the hour of twilight, at the moment when the light of day no longer suffices to enable him clearly to distinguish objects, and when he is conscious that, notwithstanding all his precautions, he is liable to lose his way.” PART FIRST. MORPHOLOGY OF THE BACTERIA. CHAPTER I. ORGANIZATION OF THE BACTERIA. WueEN bacteria develop in a liquid in a suffi- cient quantity, they become visible to the naked eye. They appear either as a slight cloud, or gathered in little masses in the liquid, or forming a pellicle upon its surface, or as a deposit upon the walls of the vessel and upon the objects contained in the liquid. However, we must hasten to say with M. Cohn, that the fact of the absence of all turbidity in a liquid does not exclude the possi- bility of the presence of bacteria. In liquids more dense than water (serum, lymph, etc.), when the refractive power of these corpuscles is the same as that of the liquid, their presence may not be revealed by the naked eye. We will add that sometimes their color serves to indicate their presence in a liquid, although this color is often very feeble, and can only be perceived when a considerable thickness of the liquid is examined. If we examine these clouds, these accumulations, these deposits, with the microscope, we see that 28 MORPHOLOGY OF THE BACTERIA. they are formed of a myriad of little bodies iso- lated or grouped, globular or linear, gifted or not with motion, sometimes colored. These variations constitute so many characters which require to be studied with some detail. § 1. BactrEerra IN GENERAL. Form. — The bacteria, as understood to-day by most botanists, when considered in their separate state, are of two principal forms, — globular bod- ies, or monads, and bodies more or less filiform, or bacteria properly so called. The globular bacteria comprise organisms round- ed, ovoid, sometimes elongating themselves into a tube (Warming). The Monas crepusculum of Ehrenberg may be taken as a type. This form includes also the Micrococcus of Hallier, the M- crosporon of Klebs, the round forms of the Amy- lobacter of M. Trécul, and perhaps the Microzyma of M. Béchamp. We will see farther on that these are very probably phases of development of the spores of bacteria, properly so called. The bacteria, not globular, present a greater diversity of form; they may be straight, undu- lating, or twisted in a spiral. The rectilmear bacteria are in some exactly cylindrical throughout their whole extent; and in this case they form very short cylinders, as in the Bacterium, Cohn, or cylinders of which the length is several times as great as the thickness, as in the Bactéridies (Bacillus ulna Cohn); others are ORGANIZATION OF THE BACTERIA. 29 swollen in the middle, with their extremities rounded, such as certain forms of Vibrio serpens (Warming); others again are fusiform, swollen in the middle and attenuated at the extremities, — Bacterium fusiforme (Warming); rectilinear bac- teria swollen at the two extremities are met during the life of certain species, B. lineola and B. termo, for example, above all when they are transported to a more favorable medium: this modification usually precedes segmentation ; final- ly, one meets sometimes bacteria swollen at one extremity only; the swollen part presents often a clear point and sometimes an evident spore: we shall see later the signification of this peculiarity. With these claviform bacteria we may include the Bacterium capitatum Dav., the Helobacteria of Billroth, and certain Amylobacter, with heads of the Ficus carica, etc. (Ch. Robin). The undulating bacteria constitute the Vibrios properly so called (V. rugula, serpens, etc.). The spiral bacteria of which the turns are more or less elongated are named Spirillum, Spiro- cheta, etc. Dimensions. — The dimensions of the bacteria oscillate between the most variable limits, but in’ a general way it may be said that they are the smallest of all microscopic beings. Some of them are situated at the extreme limit of our highest magnifying powers; and their proportions, as to 380 MORPHOLOGY OF THE BACTERIA. length and thickness, are comprised within the limits of errors of observation. The globular bacteria are the smallest, and the dimensions of some species are so minute that they cannot be measured directly. The largest are the Spirillum, which attain a length of 32; of a millimetre. Between these two extremes, there are all intermediary sizes possible. The dimensions of some of the bacteria are given below: — Monas vinosa, 0.5 to 1 p, in diameter; length 3 to 4 pw. Bacterium termo, breadth 0.6 to 0.8 w; length 2 to 3 pw. Vibrio lineola, breadth 0.5 to 1 w; length 8 to 8 p. Bacillus ulna, » OTtolw; , Sd5to8m B. anthracis, » L to2p; , 10tod04u. Spirillumvolutans, ,, Tes » 10to40 yp. Several authors, considering exclusively this character of dimensions, have divided the monera and the bacteria according to their size. Thus Hoffmann recognizes in addition to the monera, only the microbacteria, the mesobacteria, and the macrobacteria. In the same way Billroth classi- fies the monads according to their dimensions into micro, meso, mega coccos, and the bacteria into macro, meso, mega bacteria. Finally, Klebs sep- -~ arates the Micrococcos from the Microsporines, which do not differ from them except by their smaller dimensions, both forms being able to pass to the state. of bacteria (rods). ORGANIZATION OF THE BACTERIA. 31 Color. — The phenomena relating to the color of bacteria have only recently been pointed out. “ But little attention has been given to the color of the bacteria, regarded generally as colorless,” said M. de Seynes in 1874; and recently M. de Lanessan, “ The bacteria are ordinarily quite color- less.” However, M. Cohn had already insisted upon the globular bacteria chromogenes, or of pig- mentary fermentation, and upon the colors pro- duced by different monads, which have long since been studied by microscopists. Upon this subject, let us observe that the bac- teria which are colored belong to two very dif- ferent groups. First, colored organisms always known as such, but which were not formerly in- cluded with the bacteria, as the different monads, which have become the Micrococcus prodigiosus, cyaneus, aurantiacus,Cohn, etc.; the second group includes the bacteria properly so called, which absorb the coloring matter of vegetables upon which they are fixed as parasites, or of the media in which they live. This is the case with the bac- teria observed by M. de Seynes upon the Penicii- lum glaucum, and perhaps with the Vibrio syn- canthus and syncyanus, Ehrenb., which give to milk a yellow or blue color according to the species. We will return to this subject when we speak of the nutrition of the bacteria. As to the purple-colored monads, they have been especially studied as early as 1838 by Dunal, then by Morren and Ehrenberg, and in our own day by Ray-Lankester, Cohn, Klein, and finally 32 MORPHOLOGY OF THE BACTERIA. by Warming and Giard. They are found in va- rious media — in sea-water, in hot sulphur springs, in fresh water containing animal or vegetable mat- ter in a state of putrefaction. They appear some- times upon bread, meats, and in general upon cooked food placed in a humid atmosphere. The different colors which they present are red, yel- low, orange, and blue. It is probably to anal- ogous organisms that we must attribute the blue color presented by pus under certain circum- stances, the green and blue color studied by M. Chalvet, and the orange-yellow, bright red, and blue colors observed by C. Eberth in perspi- ration. In Norway, red bacteria appear in summer in such masses that the borders of the sea are some- times colored of an intense red (Warming). Movement. — The bacteria are met in two dif- ferent states. They are active or motionless; but it is now well settled for the greater number that the same species may present itself sometimes in a state of repose, sometimes in a state of move- ment. The movements of the bacteria are of two kinds, —a movement of the corpuscle upon itself and a movement of translation. The first is sometimes nothing more than a molecular or brownien move- ment, which occurs in the smallest forms. But at other times it is more extended, and consists in a movement of rotation round the axis, or a bend- ing of the body. This flexibility is, above all, ORGANIZATION OF THE BACTERIA. 33 observed in the long forms, the Bacillus, the Vib- rions, ete. As to the movement of translation, it is very variable; at one time slow, at another rapid, it is in relation with the length and form of the bacterium. M. Cohn has well described all the modifications of movement in the following lines : — “‘ Almost all the bacteria possess two different modes of life, characterized by repose and by movement. “Tn certain conditions, they are excessively mobile; and when they swarm in a drop of water, they present an attractive spectacle, sim- ilar to that of a swarm of gnats, or an ant-hill. The bacteria advance, swimming, then retreat without turning about, or even describe circular lines. At one time they advance with the ra- pidity of an arrow, at another, they turn upon themselves like a top; sometimes they remain motionless for a long time, and then dart off like a flash. The long rod-bacteria twist their bodies in swimming, sometimes slowly, sometimes with address and agility, as if they tried to force for themselves a passage through obstacles. It is thus that the fish seeks its way through aquatic plants. They remain sometimes quiet, as if to re- pose an instant: suddenly the little rod commences to oscillate, and then to swim briskly backwards, to again throw itself forward some instants after. All of these movements are accompanied by a second movement analogous to that of a screw which moves in a nut. When the vibrios in the 3 34 MORPHOLOGY OF THE BACTERIA. shape of a gimlet turn rapidly round their axis, they produce a singular illusion: one would be- lieve that they twisted like an eel, although they are extremely rigid.” The causes of these movements have been sought, at first, in the supposed animal nature of the bac- teria, and the movements assimilated, consequently, to voluntary movements ; but this opinion can no longer be sustained, as similar movements are to be seen in a great number of vegetable organisms, such as the diatoms, the oscillatoriz, the spores of algze and some fungi, etc. They have also been attributed to the existence of locomotor appen- dices (Ehrenberg); but, although the cilia, denied at first by most microscopists, have been seen since in nearly all the bacteria, the botanists who have best studied them, M. Warming, for example, rec- ognize that it is scarcely probable that these or- gans are the cause of their movements, for “ one meets some examples in which the body remains motionless while the cilia are in violent agitation, and others in which the body moves while the cilia remain inert, or dragging behind.” The movements appear to depend rather upon the nutrition, or respiration, and especially upon the presence of oxygen (Cohn); indeed when this gas is wanting the bacteria become motionless. Immobility may also be produced by want of nutriment, poisoning by different toxic substances, (chloroform, iodine, etc.), dessication, etc. The attempt has been made to use the charac- ters derived from the existence or absence of ORGANIZATION OF THE BACTERIA. 35 motion, and ‘the form of the bacteria, in order to classify them ; but what has just been said shows clearly that these transitory phenomena cannot be taken for generic or specific characters. Structure. — It was for a long time believed that the bacteria were constituted of amorphous masses of protoplasm, or of solid rods. The researches of Hoffmann have shown that they have a true cellu- lar structure. We shall describe, then, succes- sively, their membrane, the contents, and the cilia, which may be considered as belonging to the pro- toplasm. Cell-membrane. —The extreme minuteness of the bacteria usually prevents a direct demonstra- tion of the cell-membrane, and the existence of this envelope has not, heretofore, been clearly demonstrated except by indirect proofs; chemical reactions, for example. Thus Hoffmann verifies the existence of a cellu- lar envelope when “ the contents, which is a trans- parent plasma, are partly coagulated, as sometimes happens, or disappear, and are then replaced by air which shows precisely the form of the normal bacterian cell.” Warming, also, has not been able to see the membrane, “which only appears dis- tinctly when a vacuole has formed just against the periphery.” On the other hand, the action of chemical agents upon bacteria proves that they have an envelope of cellulose, which is colored by tincture of iodine ; 36 MORPHOLOGY OF THE BACTERIA. is not destroyed by caustic potash, ammonia, or even acids; and resists putrefaction for an ex- ceedingly long time. In this respect, it resem- bles the membrane of cellulose of vegetable cells (Cohn). We should add that Cohn claims to have suc- ceeded with high powers in seeing directly the cell-membrane. On the other hand, Warming has never succeeded in so doing. The last observer remarks also that the resistence of bacteria to acids, to alkalis, etc., does not seem to prove the existence of a membrane, “inasmuch as this may be the result of a particular condition of the plasma, which in all the bacteria is of a more con- sistent nature than in other plants.” Finally, the membrane may be, in certain bac- teria, tender, flexible and susceptible of move- ments of torsion. In others, it is rigid and incapable of bending. Cohn thinks also that it may swell and dissolve into mucilage, a fact which would explain the origin of this substance in the Zooglea. Protoplasm.— The contents of the cell is a nitrogenous substance, generally colorless, more highly refractive than water. In the smallest species, this protoplasm appears homogeneous; but in the bacteria of medium size, and above all in the large species, the contents of the cell encloses portions more highly refractive, vacuoles, special granules, and sometimes diverse coloring matters. ORGANIZATION OF THE BACTERIA. 37 Cohn has first pointed out the movements of the protoplasm, in which currents occur, above all in the central portion, the peripheral portion remain- ing homogeneous and motionless. The vacuoles are also found in the central portion; Warming, however, who has observed them in Monas Okenii, Vibrio rugula, V. serpens and Spirillum undula var. littoreum, has sometimes seen them in the mid- dle of the plasma, at another near the exterior wall. The granules which are seen in the protoplasm “were considered by Ehrenberg as stomachal vesi- cles or ovules. They are of two sorts; the one, highly refractive and not bordered by a dark circle, are considered by Warming as nothing more than mere compact. masses of protoplasm; the second, also highly refractive, but surrounded by a dark circle, resemble drops of oil, and have been taken for fat granules; but the recent researches of Cramer, Cohn, and Warming have proved that some of them, at least, are formed of crystalline sulphur. They are not soluble either in hydro- chloric acid or in water, but they are dissolved in absolute alcohol, in hot caustic potash and sulphite of soda, in nitric acid and chlorate of potash at ordinary temperatures, and in bisulphide of carbon, when the membrane, which is permeable with dif- ficulty, has been previously destroyed by sulphuric acid. Although their small dimensions and great refractive power prevent them from being dis- tinguished with certainty as crystals of sulphur, as they are doubly refractive to polarized light their crystalline nature cannot be doubted. 38 MORPHOLOGY OF THE BACTERIA. These globules of sulphur have been observed in Monas Okenii, Bacterium sulphuratum, Ophi- domonas, and the different species of Beggiatoa, both in fresh water, in putrid sea-water, and in thermal sulphur waters. It will be seen when we speak of the physiology of these organisms what their réle is in the elimination of sulphur and the formation of sulphuretted hydrogen. We have said, in speaking of the colored bac- teria, that some borrow their color from the sur- rounding medium, and that others, on the contrary, have a color of their own. The protoplasm of the latter contains a granular coloring matter, which is ordinarily yellow, blue, or red. The red color- ing matter is most common, and this has been best studied, and appears to be the best known. One of. these colors which gives a pink tint (peach color) to Bacterium rubescens, Ray-Lank. ( Clathrocystis roseopersicina, Cohn); Monas vinosa, Ehrb., Jf. Okenii, Cohn; M. gracilis, Warming ; Rhabdomonas rosea, Cohn; M. Warmingii, Cohn; ° Ophidomonas sanguinea, Ehrb.; Merismopedia littoralis, Rabenh.; etc., has been studied by Ray- Lankaster, who has given to it the name of bac- terio-purpurine. It is insoluble in water, soluble in alcohol, ether, carbolic acid, glycerine, and. fatty oils,— characteristics which make it resemble chlorophyll. It has also a characteristic spectrum. Other red coloring matters which appear to be different have been found in Monas prodigiosa, Ehrb.; Bacillus ruber, Cohn ; and Micrococcus ful- vus, Cohn. These should not be confounded with ORGANIZATION OF THE BACTERIA. 39 the purple coloring matter of other algx, as that of the Porphyridium cruentum, which comes from a mixture of chlorophyll and of phycoerythrine. The bacteria never contain chlorophyll. In this connection, it is interesting to recall the protoplasmic constitution of the Amylobacter of Trécul. These organisms are, according to Van Tieghem, bacteria, to which he has given the name of Bacillus Amylobacter, and which does not dif- fer from B. subtilis, except by a specific character, extremely transitory, — the presence of amorphous starch, formed and stored in reserve during the period of growth, to be again used later, and con- sumed during the process of reproduction. Cilia. —These appendages which were described by Ehrenberg in the Bacterium trilocular have not been seen since. To-day, recent researches permit us to say that cilia exist without doubt in all the true bacteria, — Bacillus, Bacterium, Spi- rillum. They have been perceived in a great number of forms,— Spirillum volutans, Sp. undula, Vibrio rugula, Spiromonas Cohnu, Vibrio ser- pens, and several species of Bacillus. It is only in the smallest of the bacteria that it has hitherto been impossible to demonstrate their presence. They have, however, been recently seen by Dal- linger and Drysdale in Bacterium termo. Warm- ing has perceived as many as two or three on one extremity in Ophidomonas sanguinea Spirillum volutans var. robustum, and Vibrio rugula. PLATE I. Taken from ‘‘ Monthly Microscopical Journal,’ of Sept. 1st, 1875. Fie 1.—a. B. termo magnified with the same power as b, which is a specimen of Spirillum volutans, showing flagella at each end. Fie. 2. — B. termo, as seen with a power of about 600 diameters. Fie. 3. — The same as seen with J; and second eye-piece (3,700 diameters). Fig. 4. — B. termo, seen with flagellum at one end, the light com- ing in the direction of the arrow. Fic. 5.— The same object when it moved at right angles to its former position, the light coming from the same direction, causing the sight of the flagellum to be lost. Fic. 6 represents one B, termo which was in a still condition, but one flagellum moving. The light came in the direction of the arrow. When the end marked 2 } was in focus, a flagellum was seen, but none at the endc. When the end marked 1 a was fo- cused carefully, the flagellum at that end was seen, and lost at the end d. Fic. 7. — The true form of B. termo. Fic. 8.— The form as shown by the ‘‘ supplementary stage ”’ il- lumination before flagella were found, showing the pointed ter- mination of the body at a, 0. The Monthly Microscopical Journal Sept 1.1875 Plate I. Ca x 1300 duninished ay da ee AMersel Lith FLAGELLA ON BACTERIUM TERMO By W.H.Dalhnger, FR MS and J.J. Drysdale, MD, ER.M.S ORGANIZATION OF THE BACTERIA. 41 EXTRACT FROM PAPER “ON THE EXISTENCE OF FLAGELLA IN BACTERIUM TERMO,” BY W. H. DALLINGER, F.R.M.S., AND J. J. DRYSDALE, M.D., F.R.M.S. “Tn the summer of 1872, some very fine specimens of S. volutans came under our notice, and were carefully examined. We were enabled fully to confirm Cohn’s discovery, and demonstrated repeatedly the presence of a pair of swiftly lashing flagella. The drawing at b, Fig. 1, was made from a specimen magnified 1,300 diameters (diminished by 3). “ Having closed for the present our Monad researches, we have been stimulated by the hope that the experience gained by these might enable us to prosecute similar investigations into the true life history of bac- teria. We have commenced the work this summer, and, guided by the analogy of S. volutans, we have been led to make several continuous efforts to find whether or not there existed a flagellum or flagella in B. termo. The task, of course, under the best circumstances, must be a aw difficult one, from the extreme niinuteness of the object. We tried each of Powell and Lealand’s powers successively, from the y4 to the 34s, but with no definite result. Repeatedly we both saw vortical action at both the distal and proximal end of the termo, but could not absolutely see the organ causing it. But in the process of our investigations we made very close and careful observations on the fission of this form: we do not purpose now to describe the process, but merely to point out a phenomenon that further confirmed our suspicion of the presence of an invisible filament. In separating into two, the jointed rod of sarcode which is in process of division shakes to and fro at the constriction, as if the constricted part were a hinge; and at length a clear separation takes place to quite the length of the original termo (sometimes longer), and there is no visible connection between them; nevertheless they act as one crea- ture, so that if one moves in any direction, the other goes with it, just as the two parts did before separation; showing that, although we cannot see the con- nection, there must be one; and the presumption was that it was a fine filament, such as we detected in the fission of some monads.1_ We could make no further progress in the question apparently ; but our attention was called to the new 3th objective prepared by Messrs. Powell and Lealand, with which we were soon supplied. We used it at first with the ‘supplementary stage’ for very oblique illumination, supplied by the same makers, and this has the advantage of throwing the light in only from one direction. We were soon convinced of the exquisite per- formance of the glass when used as an immersion. Amphipleura pellucida was not merely seen to be striated clearly and sharply, but the striae “M. M.J., vol. a., p. 55; and vol, xi., p. 8.” 42. MORPHOLOGY OF THE BACTERIA. were resolved into beads with the third and fourth eye-pieces. In like manner the fine striz in Surirella gemma were instantly shown to be beaded, with perfect and brilliant definition, with the second eye-piece. Navicwa rhomboides and an extremely delicate specimen of Pleurosigma attenuatum which had resisted everything below a yyth immersion, showed beaded strie perfectly. We were therefore encouraged to try again to discover flagella in the termo. Some of our specimens, nourished in Cohn’s nutritive fluid, were placed in a drop of distilled water, and put upon the supplementary stage on an ordinary slide covered with the thinnest cover. The utmost delicacy and tact in manipulation of the light is the great desideratum; but, with this, enough may be secured to work with the fourth eye-piece. The light may be made to enter the objective at almost every angle, but it is always projected in a direction at right angles to the stage; and the first thing we observed when the objects were sufficiently slow in their movements, and at right angles to the light, was that the ends of the termo, which we (and all other observers, as far as we know) had taken for round, proved themselves to be conical, terminating in a sharp point. The usual appearance of B. termo, as seen with a magnification of about 600 diameters, is seen in Fig.2; whilst the same seen with a magnifying power of 3,700 diameters (4;th and second eye-piece) is seen in Fig. 8, where a globular granule is seen in the end of each half. But with the method above referred to, the best condi- tions being secured, the two ends of the bacterium were distinctly pointed, as seen at a b, Fig. 8, and after nearly five hours of incessant endeavor a flagellum was distinctly seen at one end of each of two termos which were moving slowly across the field. The discovery was not sudden and transient, but lasted for at least twenty minutes. The exquisitely delicate flagellum was lashing rapidly the whole time; and one of its frequent conditions is shown in Fig. 4, the arrow indicating the direction of the light: but if the termo turned round at right angles, as in Fig. 5, all trace of the flagellum was gone, showing that its discovery depended entirely, all things being equal, upon its position in regard to the light. “But this observation was made only by one of us, the other not being present; and in pursuance of our plan we determined to see it again, convincing ourselves separately, and then together. After many hours of labor, this was accomplished ; and Fig. 6 shows one of two instances which we both saw together at the same time and in the same instru- ment. It was lying still, obliquely across the field, the light coming in the direction of the arrow. Both ends were not perfectly in focus at the same time, but in focusing the end marked 2 b (F%g. 6) the flagellum was distinctly seen, and was seen also to coil and lash; but no flagellum was then seen at the end c of the same object; but by bringing it into delicate focus it presented the aspect seen at 1 a (Fig. 6), which really represents the same object at the same time, only with the other end in the focus, while the end marked d corresponding to 2 b of Fig. 6 was in its turn slightly out of focus, and the flagellum lost to view. This ob- servation, made together, was as satisfactory as could be desired; and it ORGANIZATION OF THE BACTERIA. 43 was thus demonstrated that there was a flagellum at both ends of the or- dinary B. termo. “Tt will of course be understood that it is by no means an easy matter to secure the demonstration ; and whenever we repeat it, it must always be with nearly the same amount of trouble and patience, although we can now with the ordinary condenser detect the vortical action, both in front and (occasionally) behind the termo, as we never did before. But the demonstration of the ultimate structure of a fixed object —as for instance Amphipleura pellucida — must be looked upon as a matter of great ease in comparison; and that for many reasons, the foremost being the motion and the minuteness of the object, the swift play of the flagella, their similarity in optical properties to the fluid in which bacte- ria live, the difficulty of retaining them in focus, and of getting them in such a position in relation to the light as to make demonstration possible. Of course, all this would be removed if dead bacteria would answer, but they very rarely (indeed only once) have done so with us. The flagel- lum needs to be in slow motion to properly show itself; for even with the more delicate and minute monads it is a difficult thing to show the flagella in dead forms, since in the majority of cases they appear to be attracted round the body of the creature.” § 2.—Or THe Dirrerent Moves of GROUPING OF THE BACTERIA. The bacteria are found in different media in two states, — free, isolated (unicellular bacteria), or united several together, either in chains, in filaments, or in masses of greater or less extent, and sometimes by the aid of a mucous substance in which they are imbedded. The free unicellular bacteria are found in the Spirillum, Bacillus, Monas, etc. When they are united, they are grouped in the following modes : — 1. Form of a little chain: Torula, Leptothrix. — The usual method of multiplication among the bacteria is by fission (“scissiparité”); each cor- puscle divides transversely, and gives birth to two 44 MORPHOLOGY OF THE BACTERIA. new individuals, which sometimes become sepa- rated completely the one from the other, to form unicellular bacteria, sometimes remain united; and segmentation again occurring in each portion, a chain is formed of articles more or less numerous. When these chains are formed of spherical bac- teria, they have been called torule; if they are formed of filiform bacteria, they correspond to leptothriz (Robin). The morphological difference between the torula and the leptothrix consists in the fact that in the first the articles are separated by constrictions, while this is not the case in the second. It is also to be remarked, according to Cohn, that the microbacteria never take either of these forms. Warming states, however, that he has met the torula form in Bacterium lineola, B. catenula, and B. termo (°). Billroth has called these two forms of bacteria streptococcos and streptobacteria. He has even considered it necessary to create the words diplo- coccos and diplobacteria for organisms constituted only of two articles. 2. Form of Zooglea.— Generally, when bacte- ria are rapidly multiplying, they remain grouped in masses, swarms, or Zooglea. In the latter con- dition, they are closely pressed against each other in the midst of a viscous substance, hyaline, ho- mogeneous, colorless, and constituting masses more or less diffused or definite, in irregular globes, bunches, or tubes, swimming in the water or near its surface. When the bacteria multiply abundantly, the cells become removed from each ORGANIZATION OF THE BACTERIA. 45 other, so as to leave between them greater inter- vals. The masses sometimes attain a diameter of several centimetres. The gelatinous substance in which the bacteria are included seems to be produced by a thicken- ing and jellification of this cell-membrane, or by a secretion from their protoplasm, but the latter view seems more plausible than the former (De Lanessan). It is commonly the spherical bacteria (JMicro- coccus) and the microbacteria (Bacterium) which are found in this state. The filiform bacteria and the spirilla are never found in gelatinous masses (Cohn). Ray-Lankes- ter, however, claims to have met the Spirillum tenwe, in the form of zoogleea, and Klein the Spi- rillum undula and rosaceum (Warming). The form of Zooglea, properly so called, gelat- inous and thick, has never been found by Warm- ing in infusions of sea-water. According to the terminology of Billroth the zoogloea are called gliacoccos and gliabacteria (from yA/a, mucus substance). 3. Form of Mycoderma. — In certain cases, the bacteria unite on the surface of the water, or of the liquid in which they are developed, to form a thick layer, a sort of membrane. This production called mycoderma by Pasteur is a sort of zooglea, but differs from it by the absence of the interme- diary mucus substance. The bacteria are, how- ever, motionless, although living, since they come to the surface to be in contact with oxygen, which is necessary to them. 46 MORPHOLOGY OF THE BACTERIA. The petalococcos and petalobacteria of Billroth correspond with the mycoderma of Pasteur. 4. Swarms. — We have seen that the filiform and spiral bacteria do not, usually, form zooglea. These microphytes are either disseminated and free, or united in swarms. This formation may be seen, for that matter, in all the bacteria, when, thanks to abundant nourishment, they multiply rapidly and gather together in considerable masses. They are very active in these swarms, whilst in the zooglea the corpuscles are motionless, because of the intermediary glairy substance. Pulverulent precipitate. — When the nutritive elements are exhausted in a liquid, the bacteria cease to multiply, fall to the bottom of the recep- tacle, and the liquid gradually becomes clear. The deposit formed in this manner may acquire a thick- ness very appreciable to the naked eye. The bac- teria which form this precipitate are not dead, but in a state of temporary repose; and if a new sup- ply of nutritive material is added to the liquid, they are seen to multiply anew, until this has been exhausted (Cohn), PLATE II. a Fic. Fic. Fic. 3. PLATE II. DIFFERENT MODES OF GROUPING. From photo-micographs made in Havana and New Orleans ; copied by permission of the National Board of Health. Fie. 1. — Torula form of spherical bacteria (Micoderma aceti Pasteur) from rotten banana, New Orleans, April, 1880. > 1500 diameters by Zeiss’s ;4, in. objective. Fie. 2. — Zooglea form of spherical bacteria developed in culture- cell containing blood of leper. > 600 diameters. Fie. 38. — Mycoderma, from surface of foul gutter-water. New Orleans, April, 1880. > 400 diameters by Becks, 4 in. objective. Fie. 4. — Leptothrix form of desmobacteria developed in yellow- fever urine, exposed in laboratory, Havana, July, 1879. x 400 diameters by Becks, 4 in. objective. CHAPTER II. CLASSIFICATION OF THE BACTERIA. § 1.— Position or THE BACTERIA. TuE place of the bacteria in the scale of beings, for a long time undetermined, demands to be established with precision; not only for the natu- ralists, who only view the question from a system- atic point of view, but above all for the biologists who study the réle of these organisms in the chem- ical or pathological phenomena with which they are associated. According to Ch. Robin, not to define the animal or vegetable nature of these organisms, “ is for them as grave as it would be for a chemist to leave undecided the question as to whether it was nitrogen or hydrogen, urea or stearine, which he had obtained from a tissue, or of which he is following the combinations in certain operations.” This determination is, to-day, possible ; and, if there are still some differences of opinion among naturalists as to the place of the bacteria among the cryptogams, there is but one opinion as to their vegetable nature. It is surprising to see a savant like M. Pasteur “not to pronounce positively upon the vegetable CLASSIFICATION OF THE BACTERIA. 49 or animal nature of several of the ferments which he has studied,” and of which some belong to the bacteria. We shall first indicate rapidly the characters which permit us, at first, to recognize certain spe- cies of bacteria as organized beings, to determine if they are animal or vegetable, and finally to classify them either among the algze or among the fungi. Distinction of Bacteria from Inorganic Sub- stances. — The question as to whether bacteria are organized beings can only be raised in relation to the smallest species, those Micrococct which are scarcely perceptible with the highest powers; the organized nature of the other organisms of the same group has never been questioned, even by the earliest observers, who all, since Leeunhoeck, have, without exception, taken them for animals or vegetables. But the smallest forms of bacteria may be confounded with various matters, with organic particles, molecular granules, fat globules, etc. ‘ These productions, which are found in con- siderable quantity in the liquids or in the tissues of animal or vegetable origin, often resemble so closely, in form, size, and grouping, the spherical bacteria, that it is absolutely impossible to guard one’s self against confusion, unless the most mi- nute precautions are taken in making the observa- tions” (Cohn). The detritus, the amorphous powder of precipi- tated molecules of inorganic substances, even when 4 50 MORPHOLOGY OF THE BACTERIA. they exhibit the brownien movement, are ,easily enough distinguished from Micrococci by optical signs, their angular form, their less refractive power, and finally by their reaction with certain chemical agents; above all if they are mineral substances, crystalline bodies, etc. It will not be the same with molecular granules of organic nature. They have as common charac- ters, their rounded form, their notable refractive power, movements. Nevertheless, their form is less regular, more angular, their color variable, their refractive power always less. In doubtful cases, Tiegel has given a method which enables us to dis- tinguish them from Micrococci. It consists in warming the glass slide which supports the cor- puscles under examination, if they are “ Coccos,” they are seen to move in a manifest manner. ‘This does not occur in the case of molecular gran- ules. It is these productions which render it very difficult to observe the phenomena which occur during the coagulation of milk. The caseine sep- arates in the form of extremely minute globules having a very rapid molecular movement. But we may distinguish these from bacteria by the use of liquor potasse, which dissolves the former without attacking the latter. As another example of pseudobacteria, I will mention, after Cohn, the form which fibrine as- sumes when it separates from the plasma of the blood. It disposes itself in very slender filaments, closely resembling filamentous bacteria. CLASSIFICATION OF THE BACTERIA. 51 Fat globules, which are found of all sizes, are often of the same dimensions as Micrococcus, and are very difficult to distinguish from the latter. The difference in refractive power is slight, and the action of re-agents, such as ether, is not cer- tain in mucilaginous solutions. Hiller, who has paid especial attention to the means of recognizing: bacteria, divides them into two groups : — A. The optical signs : comprising 1. The charac- teristic vegetable form, rods, leptothrix, this he recognizes as of little use, as in this case there is no doubt; 2. The characteristic movements of the monads; 38. The mode of growth and of multipli- cation; 4. The mode of junction of the granules. B. The chemical signs: 1. False zooglea become softened and diffluent under the action of liq. potassze, and are coagulated by the direct applica- tion of alcohol; 2. In sections of tissues, after an hour of maceration in liq. potasse, diluted jth, the monads are colored brown by iodine, while fat granules are not. But, in truth, the method of cultivation, ex- tolled by Cohn and Wollf, is the best means of distinguishing the bacteria. “The distinction of pseudobacteria,” says the first of these authors, “from veritable globular bacteria is a problem which our microscopists cannot resolve, in every case, with the desirable certainty. It is only by a study of their mode of development that this distinction can be made. The globules which di- vide and develop in form of chains are organized ‘beings ; when this does not occur, we are dealing with pseudobacteria.” 52 MORPHOLOGY OF THE BACTERIA. This is not, however, exactly the opinion of Nageli, who seems to consider movement as the surest distinctive characteristic. “There are,” he says, “but three distinctive signs which enable us to recognize with some certainty that granules under observation are or- ganisms, — spontaneous movement, multiplication, and equality of dimensions, united with regularity of form. “The most certain character is movement in a straight or curved line, —a movement which inorganic granules never present. One should take care not to be deceived by movements which are caused by currents in the liquid under observation. Nor should one allow himself to be deceived by the tremulous motion, called molecu- lar movement, in which the granules do not really change their position. These movements are seen in most cells, and even in those of the Schizomy- cetes, and inorganic bodies themselves present it. “‘ Multiplication is a character less important than movement. When among granules some are found united in pairs, it may be supposed with probability that division and multiplication are taking place. When rods are bent at an angle, one may predict their division in two parts. “ Finally, as to size and form. Granules of dif- ferent size and of a more or less irregular form ought not to be considered as belonging to the group of segmented fungi; if, on the contrary, the granules offer dimensions perfectly equal, and a spherical or oval form, the distinction is more CLASSIFICATION OF THE BACTERIA. 53 uncertain: they may belong to the schizomycetes or be of inorganic nature.” Place of the bacteria among organized beings. Distinction between animals and vegetables. — The characters which serve to distinguish the inferior animal organisms from the inferior vegetable or- ganisms are of two orders, optical and chemical. A. The optical characters are drawn from the general form, the movements, and the mode of reproduction. . The morphological characters have no value except among the larger species of bacteria. If we bring together a Spirillum and a Spirulina, Kiitz., their affinities will be apparent to every one. It is not the same for the large species of Bacillus, of which the relations with the Oscilla- toria are evident. The rod form seems very spe- cial, but it does not necessarily imply the vege- table nature of the organisms which possess it. Finally, the spherical bacteria, — Monas and Mi- crococcus, — resemble entirely by their form some infusorial animals. Movement is not a more special character. It is now well proved that it does not belong exclu- sively to animals, and that it is met with in a cer- tain number of the inferior vegetables. In fact, the anatomical characters are not al- ways absolutely reliable; but it is from these alone that Cohn first, then Davaine, have recog- nized the bacteria as vegetables. B. Chemical characters. Robin depends upon 54 MORPHOLOGY OF THE BACTERIA. these characters to demonstrate the vegetable na- ture of the bacteria. He takes for point of de- parture the notions of general physiology as given by De Blainville in the following points : — 1. We find in animals various elementary sub- stances of the same kind as in plants, and re- ciprocally. 2. The ternary compounds predominate, how- ever, in plants; and the quarternary, nitrogenized, are more abundant, on the contrary, in animals. 3. In both, the fundamental cellular structure is the same; at least originally for the greater number, and always in the most simple of organ- ized beings, etc. . . . “Tt results from this, then,” continues M. Robin, “that so long as there is no digestive tube one can only distinguish plants from animals by the study of their elementary principles, and of the chemical reactions which these exhibit in general ; by the study, in particular, of the reactions which the predominance of ternary cellulose principles over all others gives to plants, and that of nitro- genized principles in animals, at all periods of their existence.” Starting from this basis, Robin made numerous attempts to find in liquor ammonia, concentrated, as prepared for use in laboratories, a reagent for corpuscles of a vegetable nature. In effect, am- monia dissolves the eggs, the embryos, of all ani- mals, the bodies of all the inferior infusoria, attacks the spermatozoa, etc., whilst it leaves ab- solutely intact all the varieties of cellulose: and CLASSIFICATION OF THE BACTERIA. 55 the anatomical reproductive elements of plants, whether it is used cold or boiling. As to the other chemical characters praised during recent years, we will content ourselves with mentioning concentrated acetic acid, which causes all animal tissues to become pale, whilst it is without action on bacteria (Luckonvsky) ; io- dine, and sulphuric acid (Letzerich), etc. Hematoxyline (Luckonvsky) and fuschine (Hoff- mann) color the bacteria deeply. One ought, then, no longer to give to the bacteria, as do some recent authors, the names of microscopic ani- malcules, — infusoria, microzoa, etc., and other expressions without precision, or consecrating an error. Let us add that some naturalists of high re- pute, Hackel for example, have created for these minute beings, monera, protoplasts, flagellata, dia- toms, etc., an intermediary kingdom between the animal and vegetable, — the Protista. Place of the Bacteria in the Vegetable Series. — The vegetable nature of the bacteria once estab- lished, it remains now to determine to what class -of vegetables they belong. Are they, alge or are they fungi? This is the question which divides the naturalists. It is true that it is to-day very difficult to find a characteristic of these two classes of vegetables, both having, in a general manner, identical forms, similar reproductive apparatus, etc.; and, if it is impossible to confound a Basidiomycete with a Floridexw, for example, it is not the same when 06 MORPHOLOGY OF THE BACTERIA. one studies the inferior species. The only char- acter which appears general is the presence of chlorophyll in the alge and its absence in the fungi. But, if we adopt this distinctive character, and apply it in all its rigor, we are obliged to separate in the inferior algee some forms very nearly related, and which do not differ from their relations except in this particular. And this is ex- actly what happens in the case of the bacteria. In truth, the bacteria, although entirely with- out chlorophyll, have numerous affinities as to form, movement, etc., with the oscillatoriacee, and, according as one or the other of these char- acters have appeared to predominate, the bacteria have been classed as algee or as fungi. It is thus that Davaine, Rabenhorst, then Cohn, struck above all by the resemblance of form, mode of grouping, and of multiplication, have placed the bacteria among the algze. Cohn insists, above all, upon the affinities of the filiform bacteria with the beggiatoa and the leptothrix ; of the micrococ- cus, and of the bacterium, with the chroococcacee. He at first placed them at the commencement of this last series; but we shall see further on that: in his last publications he has disseminated them among the oscillatoriacese and the chroococcacee. Robin and Nageli, on the other hand, insist rather upon the affinities of the bacteria with the yeast plants, which are incontestably fungi, and they include them in this class. Robin says expressly: “ All the corpuscles de- scribed under the name of Bacterium termo, B. CLASSIFICATION OF THE BACTERIA. 57 punctum, etc., Zooglea, Micrococcus, and many others, are vegetable cells, spores of fungi, of sev- eral distinct species certainly; spores, or repro- ductive bodies of the first order, derived one from another, either by germination, fission, or from a mycelium; reproductive bodies, in a word, of the order of those which Tulasne has arranged under the name of conidia, etc.” Nageli establishes in the inferior fungi which produce decompositions three very natural groups. 1. The Mucorini, or mould fungi; 2. The Saccharomycetes, or budding fungi, which produce the fermentation of wine, beer, ete. ; 3. The Schizomycetes, or fission fungi, which pro- duce putrefactive processes. This last group is formed of our bacteria (Micrococcus, Bacterium), etc. Sachs solves the question by uniting the algex and fungi in a single group, the thallophytes, in which he establishes two series exactly parallel, — one comprising the forms with chlorophyll; the other, the forms which are deprived of it, and preserving in a transverse direction the morpho- logical affinities of these organisms. As this classification is yet but little known, we think it best to give it in the following table : — THALLOPHYTES. Forms with chlorophyll. Forms without chlorophyll. Cu. 1. PROTOPHYTES. A. Cyanophycee (Oscil- A’. Schizomycetes (Bac- latoriaceze, etc.). teria). B. Palmellacee. B’. Saccharomycetes (Ferments). PLATE III. Saccharomycetes and Schizomycetes (Ndgeli), developed in urine (of yellow-fever patient) exposed in laboratory of the Yellow-fever Commission, Havana, July, 1879. Reproduced by permission of the National Board of Health. Fig. 1. — Photo-micrograph made with Beck’s }-in. objective and Tolles’s amplifier. 400 diameters. Fig. 2. — Photo-micrograph made with Zeiss’s j,-in. hom. im. objective. 1,450 diameters. PLATE III. Heliotype Printing Co., Boston, CLASSIFICATION OF THE BACTERIA. 59 CL. 2. ZYGOSPORE. A. Volvocinez. A’. Myxomycetes. B. Conjuguee and Dia- B’. Zygomycetes. toms. Cu. 3. OOSPORE. A. Spheroplez. B. Celoplastez. Saprolegnia. C. Gdogoniz. Peronosporee. Cui. 4. CARPOSPOREA. A. Coleochetez. A’. Ascomycetes. B. Floridez. B’. Gcidiomycetes. C. Characeze. C’. Basidiomycetes. Our preferences are for this last mode of classi- fication, but obliged, in the description of species, to follow the classification of Cohn, the most com- plete which has been given hitherto, we must abandon it for the present. § 2. — CLASSIFICATION ; GENERIC AND SPECIFIC CHARACTERS. The numerous classifications of the bacteria of which we have given an abstract in the historical part of this work, show how variable have been the ideas of the microscopists as to the nature of these organisms. Before giving the most recent, those among which we will have to choose, it is best to study the characters upon which authors have depended for grouping the bacteria in genera and species, and to estimate the value of these characters. 60 MORPHOLOGY OF THE BACTERIA. 1. Generic and specific characters.— These have been drawn from the dimensions, form, movement and evolution of the bacteria. The size, which, according to Cohn, is the dom- inating distinctive character, is often indetermi- nable, even in employing the highest powers. Besides, for a great number of neighboring forms, the differences of measurement given as distinctive are so slight that they cannot serve in practice. Thus, according to Dujardin, the Bacterium termo has a length of 1, 7 u, and the B.punctum of 1, 7 to 0.6». Another difficulty presents itself when we examine bacteria formed of several articles. Shall we consider the length of a single article or of the chain, which consists of a number of articles, a number ordinarily variable ? The form of the bacteria and their union in colonies, also offer differences, which have been utilized; but do they depend upon differences truly specific, or do they come from foreign influences, from phases of development of the same organism? Even when one uses these as distinctive specific characters, the form is sometimes of little assist- ance; since if one refers to the descriptions of Dujardin, the Bacterium termo will be found to have a cylindrical body swollen in the middle, and the B. punctum an elongated ovoid body. As to movement, we have seen that the phenom- ena of mobility or of immobility sometimes pre- sent themselves in the same species, according to age or changes in the medium. We have left, the mode of development, the CLASSIFICATION OF THE BACTERIA. 61 phenomena of reproduction by fission or by spores, as the only character which can serve to establish our natural genera; but, unfortunately, this has only been ascertained for a small number of bacteria, the Bacillus anthracis, for example. The genera of: bacteria cannot have the same significance as among animals and superior vege- tables ; they can only be established in accordance with the most prominent characters, reserving the feeble modifications of these generic forms as specific characters. Are there distinct, well-defined, species among the Bacteria ? The microscopists have given the most diverse opinions upon this subject. Miller, Ehrenberg, Dujardin, Davaine, have admitted the specific dis- tinction of the numerous vibrioniens which they have described. Davaine, however, raises some doubts as to the absolute value of the species established in his time. ‘“ Those which are de- scribed to-day by the classifiers,” he says, “ ought to be considered as the expression of types under which are hidden a certain number of distinct species.” Cohn dwells still more upon the impossibility, in which we are to-day, of distinguishing with certainty genera and species among the bacteria. However, he is convinced that the bacteria are di- vided into species as distinctly as the other plants and inferior organisms. It is only the imperfection of our means of observation which makes it impos- sible to recognize these differences. This is above 62 "MORPHOLOGY OF THE BACTERIA. all true, he says, of the spirilla, which are not only distinguished from the rod bacteria, properly so called; but which present in their species some differences as constant as any well-defined species of alga or of infusoria. Hallier, Hoffmann, Billroth, Robin, Nageli, etc., consider the different forms of bacteria in a very different fashion. According to them they are not autonomous species, but phases of development of one or of several species. According to Hallier, we may see, @ propos of the polymorphism of the bacteria, the singular transformations which he has obtained by their cultivation. According to Billroth, the bacteria belong to a single species of plants, the Coccobacteria septica, with the exception of the Spirillwm and Spirocheta, in regard to which Billroth is not willing to give an opinion. This view has been adopted by a certain number of microscopists, and above all by the pathologists, such as Frisch, Tiegel, etc. Robin also admits the genetic relation of Micro- coccus, Vibrio, Bacterium and Leptothriz, but con- siders them the distinct and successive phases in the evolution of several species: Ist. Corpuscles described under the name of Bacterium termo, punctum, ete., Micrococcus; 2d. Mycelial fila- ments, Vibrio, etc.; 3. Bacteria, Bacteridies, Micro- bacteria, etc.; 4th. Leptothrix and forms more advanced. The opinion of Nageli corresponds very nearly with the preceding. “As much as I am con- CLASSIFICATION OF THE BACTERIA. 63 vinced,” he says, “ that the schizomycetes cannot be grouped in accordance with their action as fer- ments and their exterior forms, and that altogether too many species have been distinguished ; so, on the other hand, it seems to me very improbable that all the schizomycetes constitute a single natu- ral species. “Tam rather inclined to suppose that there exists among them a small number of species, which have little in common with the genera and species admitted to-day, and of which each runs through a cycle of determined forms sufficiently numerous. Each of the veritable species of schizomycetes is not limited to presenting itself under the different forms of Micrococcus, Bacterium, Vibrio, and Spi- rillum, but can also show itself as the agent of acidification of milk, of putrefaction, and as the agent producing several maladies.’ However, Nageli recognizes that it is necessary to distin- guish these forms, notably those of Micrococcus, Vibrio, Bacterium, and Spirillum, without, how- ever, losing from view the fact that the organisms thus classified have a very inconstant constitution, and pass continually from one form to another. Finally, other savants such as M. Pasteur, take less account of the structural characters than of the physiological functions, regarding as a partic- ular species every form of bacterium which is born constantly in a determined medium, or which causes a special kind of fermentation. Nageli opposes to this view the following objections. First, he has verified the presence, in 64 MORPHOLOGY OF THE BACTERIA. the same decomposition, of several different forms of schizomycetes. On the other hand, in decom- positions quite different, we may observe schizo- mycetes entirely similar as to their exterior form. Finally, we may change the mode of action of a schizomycete in subjecting it to a certain treat- ment. One sees that it is truly difficult to form an opinion as to the value of these species purely physiological. - To sum up, the characters which may be used in order to establish genera and species in the group of the bacteria are of small number and of very unequal value. Some, characters of form, of dimension, of movement, etc., are often difficult to determine, or have only a relative value; others, characters drawn from development and reproduc- tion, are only known in so few species that they cannot be made to serve as a basis of classifica- tion. One will not be surprised, then, to find that there is no natural classification of the bacteria, and that it is impossible for the naturalists to give one. All those that can be established are pro- visory, being only based upon the morphology of these organisms. Following the example of all the botanists, we will use an analogous classification, but without wishing to prejudge in any particular the genealogical relationship of the different or- ganisms, which we shall consider as distinct gen- era and species. CLASSIFICATION OF THE BACTERIA, 65 § 3.— CLASSIFICATION AND DESCRIPTION OF THE GENERA AND SPECIES OF THE BacTERIA. We have seen in the historical portion of this work, @ propos of the classifications which have been given of the bacteria, that, in 1872, M. Cohn, recognizing the numerous relations, absence of chlorophyll, mode of nutrition, etc., which make these organisms a natural family, divided them into four tribes : — 1. The Spherobacteria, or spherical bacteria. 2. The Microbacteria, or B. in short rods. 3. The Desmobacteria, or B. in straight filaments. 4, The Spirobacteria, or B. in spiral filaments. In the spherobacteria, Cohn has only adopted one genus, the g. Micrococcus, of which the spe- cies are divided into three series, — the pigmen- tary M., or chromogenes, the M. of fermentations, or zymogenes, and the M. of contagious affections, or pathogenes. The microbacteria include only the genus Bac- terium, with two species, B. termo, Dujardin, and B. lineola, Cohn. The desmobacteria comprehend the g. Bacillus and Vibrio ; the first established by Cohn for the rectilinear filaments is composed of the B. subtilis, Cohn (with B. anthracis as a variety) and the B. ulna, Cohn; the second, characterized by undu- lating filaments, is reduced to V. rugula and ser- pens, Auct. 5 66 MORPHOLOGY OF THE BACTERIA. Finally, the spiral filaments of the spirobacte- ria characterize the gr. Spirdllwm and Spirocheta, which might be united in a single genus compris- ing Sp. plicatile, tenue, undula, and volutans. Since then, Cohn, struck with the affinities which each of the preceding genera presents with several genera of oscillatoriacese and of chroococ- cee, from which the bacteria only differ by the absence of chlorophyll, has established a class of Schizophytes, which includes all the inferior vege- table organisms, provided or not with chlorophyll, multiplying by fission. We give below the complete table : — 2. Classification of the Schizophytes, Cohn. TRIBE 1.—GLAOGENES. Cells free or united in glairy families by an intercellular substance. A. Cells free or united by 2 or by 4: Cells spherical . . CHRoococcus, Nig. Cells cylindrical . SyNEcHococcus, Nig. B. Cells united in glairy families, amorphous in state of repose : a. Cellular membrane, con- founded with the intercel- lular substance: 1. Cells without phyco- chrome, very small : Cells spherical . . Micrococcus, Hallier. CLASSIFICATION OF THE BACTERIA. 67 Cells cylindrical . BactrRrum, Duj. 2. Cells with phyco- chrome, larger : Cells spherical . . APHANOCAPSA, Nag. Cells cylindrical . APHANOTHECE, Nig. b. Intercellular substance formed of several mem- branes enclosed one with- in the other: Cells spherical . . Guaocapsa, Kg. Cells cylindrical . GLasoTHECE, Nig. C. Cells united in glairy fam- ilies of definite form: a. Families of a single layer of cells disposed in plates: 1. Cells in fours form- ing a plane surface . MERISMOPEDIA, Meyen. 2. Cells without regular arrangement, forming a curved surface : Cells spherical, fam- ilies with reticu- lated rupture. . CLATHROCYSTIS, Henfr. Cells cylindrical, cu- neiform, families divided by con- striction . . . C@LosPHa&RIUM, Nag. 6. Families with several lay- ers of cells, united in spher- ical corpuscles : 1. Number of cells de- termined : Cells spherical, col- orless, arranged in fours . . . SARCINA, Goods. 68 MORPHOLOGY OF THE BACTERIA. Cells cylindrical, cu- neiform, with phy- cochrome, with- out regular ar- rangement . . GOMPHOSPH#RIA, Kg.’ 2. Number of cells very great and indetermi- nate: Cells colorless, very small . . . . Ascococcus, Billr. Cells colored by ) Potyoystis, Kg. phycochrome CoccocHLoris, Spr. and larger. . ) Ponycocovus, Kg. TRIBE 2.—NEMATOGENES. Cells disposed in filaments. A. Filaments not branched : a. Filaments free or inter- laced. 1. Filaments cylindrical, colorless, articulations not very distinct: Filaments very slen- der, short. . . BAcriLius, Cohn. Filaments very fine, long. . . . . Leproruris, Kg. Filaments larger, long . . . . BEae@raTo, Trev. 2. Filamentscylindrical, with phycochrome, articles well defined, without cellular re- production . HyYPHEorurRix, Kg. OSCILLARIA, Bose. CLASSIFICATION OF THE BACTERIA. 69 38. Filaments cylindrical, articulated, with co- nidia: Filaments colorless CRENOTHRIX, Cohn. Filaments with phy- cochrome . . . CHAMASIPHON. 4, Filaments spiral without phycochrome : Filaments, short, light, sinuous . Visrio, Ehr. Filaments, short, spi- ral, rigid . . . SPrIRILLUM, Ehr. Filaments, long, spi- ral, flexible . . SprrocHarTs, Ebr. with phycochrome : Filaments long, spi- ral, flexible . . Sprruztna, Link. 5. Filaments in chaplet: Filaments, without phycochrome . . StREPTococcus, Billr. Filaments with phy- ] ANaBaNA, Bory. cochrome. . . | SPERMOSIRA, Kg. 6. Filament flagelliform, slender . . . . . MASTIGOTHRIX, etc. b. Filaments united into glai- ty families by an intercel- lular substance : 1. Filaments cylindrical, colorless. . . . . Myconostoc, Cohn. 2. Filaments cylindri- cal, with phyco- chrome . 8. Filaments in chaplet . Nosroc, etc. 4, Filaments flagelliform, slender . . . . . RIVULARIA, etc. CHTHONOBLASTUS. Limnociipeg, Kg. 70 MORPHOLOGY OF THE BACTERIA. B. Filaments with false ramifi- cation: 1. Filaments cylindri- CLADOTHRIX, Cohn. cal, colorless STREPTOTHRIX, Cohn. 2. Filaments cylindri- | Catornerx, Ag. acta ee Scyronema, Ag. chrome : 8. Filament in chaplets. MerizomyRia, Kg. 4, Filaments flagelli- | ScurzostpHon, Kg. form, slender towards Guocyctus, Kg. the extremity . An inspection of this table shows that each of the genera of the ancient group of the bacteria has been placed beside some genus of oscillatori- aces, which it resembles by its organization, — Micrococcus and Bacterium, beside Aphanothece and Aphanocapsa; Bacillus, beside Leptothrix and Beggiatoa; Vibrio and Spirillum, beside Spi- rulina. . These affinities are undeniable, and the advan- tages of such a classification are manifest ; but, in a work like this, we cannot think of employing it. We preserve, then, in a distinct group the schizo- phytes deprived of chlorophyll, which may be arranged in the four primary divisions of Cohn with the exception of Sarcina, Ascococcus, Creno- ihrix, etc., and the other genera created recently by this botanist. Thus we will describe successively : — 1. The Spherobacteria of Cohn; and beside them the different Monas recently studied, — the Micrococ- CLASSIFICATION OF THE BACTERIA. 71 eus described by Hallier in several infectious mal- adies. 2. The Microbacteria. 3. The Desmobacteria, including Bacillus, Lepto- thriz, Beggiatoa, and Crenothrix. 4. The Spirobacteria, including the three genera, Vibrio, Spirillum, and Spirocheta. 5. Finally, we will give some account of the Mer- ismopedia, Sarcina, Ascococcus, Streptococcus, Myco- nostoc,. Cladothrix, and Streptothriz. 1. SPHEROBACTERIA, Cohn. The spherical bacteria are characterized by their rounded or oval form, their small size, often less than 1 p. They are ordinarily isolated, often in pairs (diplococcus), sometimes in a chain of several articles (streptococcus = torula of Cohn), the my- cothrix of Hallier and Itzigsohn, or in the form of zooglea when they are young and actively multi- plying, and that of mycoderma, when they are gathered upon the surface of liquids. They have no spontaneous movement, but a simple molecular trepidation. Functions: “The spherical bacteria are fer- ments, not producing putrefaction, but substitu- tions of another kind” (Cohn). Obs. According to the facts observed by Koch, Cohn, Pasteur, Toussaint, upon the development of certain bacteria, it is very probable that some at least of the spherobacteria are spores of Bacil- lus or of other bacteria; at least, the mzcrococct and these spores are identical in form and aspect. 72 MORPHOLOGY OF THE BACTERIA. The spherobacteria include only the genus J/i- crococcus. g. Micrococcus, Cohn (Hallier emend. — Micro- spheria, Cohn, ante). Cells colorless, or scarcely colored, very small, globular or oval, forming by transverse division filaments of two or several articles, in form of chaplet, or united in numerous cellular families, or in gelatinous masses, all deprived of move- ment. ‘ The species are divided into three physio- logical groups : — a. M. Chromogenes. 6. M. Zymogenes. ce. M. Pathogenes. Section (4): Micrococcus CHROMOGENES. The pigmentary bacteria grow in the state of Zooglea upon the surface of the substances which furnish them with nutriment. They are always alkaline; all are avid of oxygen; their morphological characters are identical, and one can only distinguish them by their different coloring properties. According to Cohn, they are veritable spe- cies; for 1. Their pigments offer the greatest diversity as to chemical action and by spectro- scopic analysis, etc.; 2. Each species cultivated in the most diverse media produces always the same coloring matter. CLASSIFICATION OF THE BACTERIA. 73 They are divided into two categories, accord- ing as the pigment is soluble or not in water. 1. Coloring matter insoluble. M. Prodigiosus, Cohn (Monas prodigiosa, Ehvb. ; — Palmella prodigiosa, Mont. ;— Bacteridium prodigiosum, Schroeter). A red gelatinous mass, pink carmine, develop- ing upon cooked alimentary substances placed in damp air, never before cooking. It has also been observed in red milk, at- tributed incorrectly to lesions of the teats, etc. (Cohn), M. luteus, Cohn (Bacteridium luteum, Schroeter). A yellow gelatinous mass studied by Schroeter and Cohn upon potatoes. 2. Coloring matter, soluble. M. aurantiacus, Cohn (Bacteridium auriantiacum, Schrceter). Little drops, or stains, more or less extended, golden yellow, cultivated by Schroeter, upon slices of cooked potato; by Cohn, upon hard white of egg. M. chlorinus, Cohn. A glairy yellowish-green pigment found upon hard white of egg, not reddened by acids, but loses its color. M. cyaneus, Cohn (Bacteridium cyaneum, Schroe- ter). Pigment deep blue, observed by Schroeter 74 MORPHOLOGY OF THE BACTERIA. upon cooked potato, and cultivated by Cohn in nutritious solutions. This coloring matter is reddened by acids, and restored to blue by al- kalies, just as that which forms when lichens are macerated in presence of ammonia. M. violaceus, Cohn (Bacteridiwm violaceum, Schree- ter). Violet-blue masses or glairy stains formed of elliptical corpuscles larger than those of M. pro- digiosus, observed first by Dr. Schneider, then by Schroeter on cooked potato. Later, Cohn has described the two following new species (1876), which should be included in this group: M. Candidus, Cohn. Stains and points white as snow, observed upon slices of cooked potato. M. fulvus, Cohn. Little rust-colored drops, consisting of cells, globular or united in pairs, in a tenacious inter- cellular substance, diameter 1.5 », observed by Eidam, then by Kirchner, upon horse dung. It is also to the genus Micrococcus that we must refer the little globular bacteria, gifted with movement, found by Eberth in white, yel- low, and red perspiration, and by Chalvet in the pus on the edges of certain wounds, but which should not be confounded with the blue color produced by a Bacterium. CLASSIFICATION OF THE BACTERIA. 75 SEctTion (B): Micrococcus ZyMoGENEs. Globular bacteria producing fermentations of diverse nature. M. crepusculum, Cohn (Monas crepusculum, Ehrb.). Globular cells, colorless, developing in all in- fusions of animal and vegetable matter under- going decomposition. M. urez, Cohn. Oval cells, isolated, diameter 1.5 p (Pasteur), 1.2 to 2 w (Cohn) or united by 2, 4, to 8 (to- rula), in a line, straight, curved, zigzag, or even in cross form. In urine of which it transforms the urea into carbonate of ammonia (Pasteur). A Torula which appears identical with the preceding Micrococcus, produces the decomposi- tion of hippuric acid into benzoic acid and gly- collamine (Van Tieghem). M. of stringy wine, etc. Globular cells of 2 y diameter, in chaplets, found in stringy wine, perhaps identical with the preceding (Pasteur). A Torulaceze quite similar is found in certain fermentations of tartrate of ammonia and of beer yeast, with or without the addition of car- bonate of potash (Pasteur). Section (c): Micrococcus PaTHOGENES. Spherical bacteria found in affections of a con- tagious nature. 76 MORPHOLOGY OF THE BACTERIA. M. vaccine, Cohn (Microsphera Vaccine, Cohn). Very small micrococci, = 0.5 p scarcely, iso- lated or united in pairs in recent vaccine virus and in the pus of variola pustules. By cultiva- tion, chaplets of from two to eight cells may be obtained, then masses containing sixteen to thirty-two cells of 10 » and more diameter. The M. of vaccine virus and of variola are identical, and Cohn regards them as different races of the same species. M. diphtheriticus, Cohn. Granular cells, ovoid, measuring from 0.35 to to 1.1 p, isolated or more often united in twos or ina chaplet of four to six cells; sometimes multiplying in colonies and extending them- selves in all the diseased tissues, decomposing and destroying them ((irtel). M. septicus, Cohn (Microsporon septicus, Klebs). Little rounded cells, of 0.5 ~, motionless and crowded in masses or united in chaplets, in the secretion of wounds in cases of septicemia (Klebs), in zoog/ea in callous ulcers, in isolated cells, united in pairs, or in chaplets in the se- rum of epidemic puerperal fever (Waldyer), in all the tissues, vessels, etc., in cases of pyemia and septicemia. M. bombycis, Cohn (Mycrozyma bombycis, Bé- champ). Cells with a diameter of 1 y, ordinarily united in chaplets of two, three, four, five, or more, in CLASSIFICATION OF THE BACTERIA. 17 the intestine of silkworms sick with “da flach- erie” (Pébrine). In a more recent work, Cohn (Beitrage, 1875, p- 201) gives them an oval form and a diameter of 0.5 » at the outside. Hallier has described many other Micrococci in diverse contagious or virulent affections. We will only refer to them in a summary manner : '— M. of the variola of animals, Hallier. Small M. endowed with active movement, furnished with a very delicate caudal append- age, sometimes united in the form of little elon- gated rods, found in pustules, spontaneous or inoculated, in the lymphatic canals and the gan- glia of animals attacked with variola. M. of rugeola, Hallier. Very small colorless M., having often a caudal prolongation, in the sputa and blood of the sick. M. of scarlatina, Hallier. M., free or in colonies, on the surface or in the interior of the blood corpuscles, or in chains. M. of epidemic diarrhea, Hallier. M. in intestinal matters with vibrios, cells, and monads. (?) 1 “Tt is quite probable that Hallier comprises, in part, under the name of Micrococcus the same organisms that I call spherical bacteria; but the doctrine of Hallier concerning Micrococcus, as has already been pointed out by Hoffmann and de Barry, is so covered by inexact asser- tions and improbable hypotheses, that it is impossible to draw any con- clusions from the facts he has observed.” — Coun, Beit. II, p. 148. 78 MORPHOLOGY OF THE BACTERIA. M. of exanthematous typhus, Hallier. M. relatively large, brown, having a rapid movement, sometimes in chains (Mycothrix), in the blood. M. of intestinal typhus, Hallier. M. very small, in repose in the blood ; larger, endowed with active motions, and furnished with contractile appendices in the dejections. M. of glanders, Ziirn. Cells free or attached to the blood globules, or even penetrating into their interior, sometimes in chains (Mycothrix) in the blood. M. in chains, very numerous, and endowed with rapid movements, in the lymphatic ganglia, the mu- cus of the frontal sinuses, and in the chancroid ulcers. MM. of syphilis, Hallier. M. numerous, colorless, free or in globules, in gonorrhoea, the primitive ulcer, and the blood of persons suffering from constitutional syphilis. Mownaps. Beside the Spherobacteria are placed the Mon- ads, not the organisms described under this name by the older microscopists, comprising micro- phytes, spores, and infusorial animals, but the Monas as understood by botanists of the present day. Thus limited, the Monads include also, be- sides some microphytes related to the Spherobac- teria, and differing from them by their greater dimensions, some organisms of doubtful affinities. CLASSIFICATION OF THE BACTERIA. 79 As in the case of the Micrococci it is very probable that the Monads are only the spores, or lower forms of bacteria higher in the scale. Cohn places the Monas vinosa of Ehrenberg with the Clathrocystis roseopersicina, Cohn (Bacterium ru- bescens, Ray-Lank.), considering it a spore of the latter. Monas vinosa, Khrb. Cells spherical, oval, regular, of 2.5 uw, often united in pairs, formed of a pink substance with granules of a deeper color, having spontaneous movements. Had., waters containing decomposing vegetable matters (Ehrb. 1838, Ch. Morren 1841, Perty 1852, Cohn 1875). M. Okenii, Ehrb. Cells cylindrical; average length 7 to 15 » (Cohn), 10 » (Ehrb.), sometimes from 60 to 80 4 (Warming), diameter 5 w; of a beautiful red color, having a rapid gyratory movement, with a cilium at the posterior extremity or two cilia at the two extremities. Hab., stagnant water (Ehrb. 1836, Eichwald, Weiss, Cohn, etc.). M. Warmingii, Cohn. Cell cylindrical, pink, containing at its two rounded extremities some deep-red granules; length 15 to 20 w, width 8 ~; movement uncertain, having a vi- bratile cilium. Hab., brackish water on the coast of Norway (Warming). M. gracilis, Warming. Cells straight, cylindrical, pink, rounded at the two extremities; length 60 yw, thickness 2 4; move- ment slow. Had., fresh water. 80 MORPHOLOGY OF THE BACTERIA. Rhabdomonas rosea, Cohn. Cells pale pink, isolated, fusiform ; eight times as long as broad, having a length of 20 to 30 pw, and a width of 3.8 to 5 w; having a slow oscillatory move- ment, the pink substance containing numerous gran- ules of darker color and vacuoles. Hab., stagnant water. Ophidomonas sanguinea, Ehrb. Cells pale pink, spiral, rigid, movement active ; thickness 3 yu, length of one turn of the spiral, 9 to 12 4. Habd., brackenish waters of Denmark (Warm- ing). Spiromonas Cohnii, Warming. Cells spiral, flattened ; 13 turn of spiral, diam. 1.2 to 3.5 w, width 1.2 to4 w. Had., coast of Denmark. 2. MICROBACTERIA, Cohn. Rod-bacteria, cells cylindrical, short, having spon- taneous movement. A single genus, — Bacterium. g. Bacterium, Duj. emend. Cells cylindrical or elliptical, free or united in pairs during their division, rarely in fours, never in chains (leptothrix or torula), sometimes in zooglea (differing from the Z. of spherical B. by a more abundant and firmer intercellular substance), having spontaneous movements, os- cillatory and very active, especially in media rich in alimentary material and in presence of oxygen. CLASSIFICATION OF THE BACTERIA. 81 We might, as in the Spherobacteria, divide the rod-bacteria into three groups: 1. the bac- teria of putrefaction, B. termo, B. lineola, and their varieties ; 2. the Bacteria of the lactic and acetic fermentations, etc.; 3. Chromogenes, B. of colored milk and pus. B. termo, Ehrb. 1830, Duj. ( Vibrio lineola, Ehrb. ex. p. 1838; Monas termo, Miiller). Cells cylindrical, slightly swollen in the middle, isolated, sometimes united in pairs, two to five times as long as wide; length 2 to 8 y, thickness 0.6 to 1.8 4; movements oscillatory. Appears at the end of a very short time in all infusions of animal and vegetable substances ; multiplies with rapidity in numerous zooglea ; then disappears as other species, to which it serves as nutriment, are developed. According to recent observations, this bacterium has cilia (Dallinger, Drysdale, Warming). Warming has also found it in the state of torwla. B. termo is the veritable agent, the first cause, of putrefaction, it is the true ferment saprogéne (Cohn). M. Warming has recently described two allied forms : — B. griseum, cells larger, more rounded ; length 2.5 to 4 p, thickness 1.8 to 2.5 ». In infusions of fresh and salt water. B. hitoreum, cells elliptical or elongated, slightly rounded ; length 2 to 6 y, thickness 1.2 to 2.4 4. Coasts of Denmark. B. lineola, Cohn (Vibrio lineola, Ehrb. ex p., Duj., Miiller, V. tremulans, Ehrb., Bacterium triloculare, Ehrb). 6 82 MORPHOLOGY OF THE BACTERIA. Cells cylindrical, straight, rarely a little twisted, larger than the cells of B. termo, isolated or united in pairs, sometimes in fours, never more; length 8.8 to 5.25 yw, thickness attains 1.25 4; movements like those of B. termo, but a little more active. Is found in various vegetable and animal in- fusions of fresh or salt water, often takes the form of zooglea containing motionless rods in their mucus substance. Warming has met it in the form of chains composed of eight to ten cells (torula). Its protoplasm is dotted with re- fractive granules. It is not known whether B. lineola constitutes a specific ferment (Cohn). The B. fusiform, Warming, differs from the preceding by the form of its body, which is attenuated at the two extrem- ities; length 2 to 5 », width 0.5 to 0.8 »; plasma not punc- tated. Beside these species, which have been well studied, may be placed the following, which demand new investigations : — B. punctum, Ehrb. Elongated rods, oval, colorless, having slow movements, oscillating, often united in pairs; length 5.2 yw, thickness 1.7 u. Diverse infusions of animal substances. B. catenula, Duj. Body filiform, cylindrical, often united in three, four, or five; length 3 to 4 yp, thickness 0.4 to 0.5 . In fetid infusions, in typhoid fe- ver (Coze and Feltz). CLASSIFICATION OF THE BACTERIA. 83 Vibrio lactic, Pasteur. “ Articles almost globular, very short, a little swollen at the extremities; length of an article, 1.6 py, of a series, 50 pw.” This vibrio seems to resemble B. catenula or B. termo. It is developed, according to Pas- teur, in sweetened liquids, where it causes the formation of lactic acid and the coagulation of the casein of milk. According to other re- searches, coagulation of casein results from the influence of a soluble ferment (zymase), and not from an organized ferment. Acetic ferment (Mycoderma aceti, Pasteur, Ulvina aceti, Ktg.). « Articles short, constricted, two to three times as long as broad; length 1.5 w, often united in long chains, forming pellicles on the surface of a liquid.” This species is also very similar to the pre- ceding. It must not be confounded with the Mycoderma vini, which may develop in the same media, but which is a fungus of the group of Saccharomycetes. The acid fermentation of beer seems to be due to a form of Bacterium resembling B. termo (Cohn), but a little larger than the type. Cohn has found it in beer undergoing acid fermenta- tion, beside oval saccharomyces, elliptical bac- teria, having movement, often united in pairs, rarely in fours, ete. Vibrio tartaric right (Pasteur). Bacteria similar to those of the lactic fermentation, PLATE IV. From “ Pasteur’s Studies on Fermentation.” Macmillan § Co., London, 1879. “The engraving represents the different diseased ferments, together with some cells of alcoholic yeast, to show the relative size of these organisms.” Fig. 1 represents the ferments of turned beer, as it is called. These are filaments, simple or articulated into chains of different size, and having a diameter of about the thousandth part of a millimetre (about y5$ inch). Under a very high power they are seen to be composed of many series of shorter filaments, immovable in their articulations, which are scarcely visible. In No. 2 are given the lactic ferments of wort and beer. These are small, fine, and contracted in their middle. They are generally detached, but sometimes occur in chains of two or three. Their diameter is a little greater than that of No. 1. In No. 3 are given the ferments of putrid wort or beer. These are mobile filaments, whose movements are more or less rapid, according to the temperature. Their diameter varies, but is for the most part greater than that of the filaments of Nos. 1 and 2. They generally appear at the commencement of fermentation, when it is slow, and are almost invari- ably the results of very defective working. In No. 4 are given the ferments of viscous wort, and those of ropy beer, which the French call filante. They form chaplets of nearly spher- ical grains. These ferments rarely occur in wort, still less frequently in beer. No. 5 represents the ferments of pungent, sour beer, which possesses an acetic odor. These ferments occur in the shape of chaplets, and consist of the mycoderma aceti, which bears a close resemblance to lactic ferments (No. 2), especially in the early stages of development. Their physiolog- ical functions are widely different, in spite of this similarity. The ferments given in No. 7 characterize beer of a peculiar acidity, which reminds one more or less of unripe, acid fruit, with an odor sui generis. These ferments occur in the form of grains which resemble little spheri- cal points, placed two together or forming squares. They are generally found with the filaments of No. 1, and are more to be feared than the latter, which cause no very great deterioration in the quality of beer, when alone. When No. 7 is present, by itself or with No. 1, the beer ac- quires a sour taste and smell that render it detestable. We have met with this ferment existing in beer unaccompanied by other ferments, and have been convinced of its fatal effects. No. 6 represents one of the deposits belonging to wort. This must not be confounded with the deposits of diseased ferments. The latter are always visibly organized, whilst the former is shapeless, although it would not always be easy to decide between the two characters, if sev- eral samples of both descriptions were not present. This shapeless de- posit interferes with wort during its cooling. It is generally absent from beer, because it remains in the backs or on the coolers, or it may get entangled in the yeast during fermentation, and disappear with it. Among the shapeless granules of No. 6 may be discerned little spheres of different sizes and perfect regularity. These are balls of resinous and coloring matter that are frequently found in old beer at the bottom of bottles and casks. They resemble organized products, but are nothing of the kind. PLATE IV. is Heliotype Printing Co., Boston. CLASSIFICATION OF THE BACTERIA. 85 with globular articles, short; diameter 1 «, united in chains of 50 yp. Decomposes racemic acid, causing the right tartaric acid to disappear, and setting free left tartaric acid. MIcRoBAcTERIA CHROMOGENES. B. xanthinum, Schroeter (Vibrio synxanthus, Ehrb.). ‘Bodies cylindrical, slightly flexible, formed of cor- puscles rarely exceeding five in number; length of an article, 0.7 to 1 w. In tainted cow’s milk, to which it gives a yellow color.” B. syncyanum, Schroeter (Vibrio syncyanus, Ehrb.). This Bacterium, which has the same charac- ters as the preceding, has been observed in sour milk, to which it gives a blue color. B. eruginosum, Schroeter. In greenish blue pus. These B. chromogenes resemble entirely the lactic vibrios, B. termo or catenula. According to Robin, colored milk contains colorless vibrios, and the coloration is due to an alga similar to Leptomitus. B. brunneum, Schroeter. Rods in a brown coloring matter in infusions of rotten corn. Following the colored Microbacteria, I place two species of Bacterium recently described by Ray-Lankester and Warming. B. rubescens, Ray-Lank., 18738. Under this name Ray-Lankester has described 86 MORPHOLOGY OF THE BACTERIA. some phases of development of Clathrocystis roseo- persicina of Cohn. Now Cohn is inclined to regard the Monas vinosa, Ehrb. as the wandering cells of Clathrocystis. On the other hand Warming has de- scribed his : — B. sulfuratum, Warming, 1876, giving it for synonymes, Monas vinosa, Ehrb.; M. erubescens, Ehrb.; M. Warm- ingii, Cohn; Rhabdomonas rosea, Cohn. It follows, then, that the Monas which we have described with the Spherobacteria should be referred to a Bacterium called sulphuratum by Warming, but which is also identical with B. rubescens of Ray-Lankester. 38. DESMOBACTERIA. Filiform bacteria, composed of elongated cylin- drical articles, isolated, or in chains more or less extended, resulting from transverse division. Un- der this form they correspond to leptothrix, Auct. (differing from torula in that the filaments are not constricted at the point of junction of the articu- lations); filaments sometimes united in swarms, never in zooglea. Movements and state of re- pose alternating and depending upon the presence or absence of oxygen, the reaction of the medium, and other conditions unknown. Some forms never exhibit movement.— Bacteridie of Davaine (Cohn). We will only preserve in the Desmobacteria the genus Bacillus, Cohn. The vibrios are rather al- lied to Spirillum because of their undulating fila- ments. However, after the exposition of the different species of Bacillus, we will say something of three genera of colorless oscillatoriaceze, which are nearly CLASSIFICATION OF THE BACTERIA. 87 related to them, — the Leptothrix, Beggiatoa, and Crenothriz. 1. Fil. with indistinct articulations Fil. very slender, short. . . . BaciLius. Fil. very slender, long . . . . LeproTHrix. Fil. thick, broad. . . . ) . ). Braoratoa. 2. Fil. articulated distinctly . . . . CrENOTHRIX. g. Bacillus, Cohn. The bacilli are characterized by slender fila- ments, straight, short or of moderate length, rigid or flexible, endowed or not with motion. One species is chromogene, the B. ruber of Cohn. Finally it is to this genus that we should refer the Amylobacter of Trécul. B. subtilis, Cohn (Vibrio subtilis, Ehrb.; Ferment butyrique, Pasteur). Filaments very slender and elongated, formed of a single cell having usually a length of 6 yu, or of two articles of which the total length is then’12 yw, or of three (length 16 yw), or of a greater number (some- times as many as twenty, with a total length of 40 to 60 and 130 w); thickness not measurable, well-defined movements of flexion, active or passive, and of trans- lation forward or backward; reproduction by fission and by globular or oval spores developing themselves in the interior of the articles (Cohn). Is found in stagnant water. Plays a great réle in the butyric fermentation (Pasteur). This B. exists in rennet, can support a temperature of 105°, and live in a medium deprived of free oxygen, in which case it takes a form céphalée, containing persistent spores, 88 MORPHOLOGY OF THE BACTERIA. which, when set free, give birth to other rods of Bacillus (Cohn). B. anthracis, Cohn (Bactéridie charbonneuse, Da- vaine). Species very similiar to the preceding, generally longer and always motionless; length 4 to 12 and even 50 y, thickness, scarcely appreciable, 0.8 to 14 » (Bollinger). The B. anthracis is developed in charbon (malignant pustule of man, sang de rate of sheep, maladie de sang of cattle, fievre charbon- neuse of horses), and in the rabbit, the rat, ete. ; never in the dog, the cat, the birds, and cold- blooded animals. It is found above all in the capillary vessels. Cultivated in suitable media, such as the aqueous humor of the eye of the ox, the Bacillus of anthrax develops spores in the interior of its filaments, which may germin- ate and reproduce rods (Koch). According to recent observations not yet published, by cultivating the B. Anthracis in the blood of the dog, a development of veritable sporangia may be obtained, containing from three to six spores (Toussaint). B. amylobacter, Van Tieghem ( Amylobacter, Uro- cephalum and Clostridium Trécul). B. occurring, like the preceding, under various forms,—in pointed cylindrical filaments of 6.6 to 26 w in length and 1.1 » in thickness, or in form of tadpole, with a spore in the terminal swelling, or of a spindle, with a spore in the middle. In fact, it does not differ from B. subtilis, except by the appear- CLASSIFICATION OF THE BACTERIA. 89 ance of starch in its protoplasm at the end of the period of multiplication. These B. are sometimes endowed with movement (Nylander). It develops in vegetable tissues, which fall into putrefaction, spontaneously according to Trécul, or introduced from without by a mech- anism still unknown. This is the essential agent of vegetable putrefaction (Van Tieghemn). B. ulna, Cohn ( Vibrio bacillus, Ehrb.). Filaments articulated, thick, and rigid, formed of one, two to four articles, straight or broken in zig- zag; length of an article 10 w, length of a filament of four articles 42 4; slow movements of rotation and of progression. Develops in various infusions of fresh or salt water. In certain cultivations, Cohn has seen large globules (spores?) form in the protoplasm. Warming believes that he has seen cilia. B. ruber, Cohn. Long rods, isolated or united in two or four, movement very active; in a red mucous sub- stance, vermillion, developed upon grains of rice. Observed by Franck and Cohn. Davaine has described five additional species of Bacteridies, which appear to be bacilli. They are :— La Bacteridie intestinal. Filaments straight, thick from 10 to 40 w in length. In the intestines of birds. La B. du levain. Filaments slender and short, of 10 to 20 yu, divided 90 MORPHOLOGY OF THE BACTERIA. ‘into two, sometimes three to four articles, identical with the B. of charbon (Davaine). La B. glaireuse. Filaments extremely slender, straight or elbowed ; attaining 10 w in length. La B. du vin tourné. Filaments very slender, of variable length, flexible, indistinctly articulated. La B. des infusions. Filaments of 10 to 20 ». In various infusions. g. Leptothrix, Ktz. The Leptothriz differ from Bacilli by their filaments being very long, adherent, very slen- der, and indistinctly articulated. Their forms are numerous. The following are the principal : — L. rigidula, Ktz. Length 100 to 150 yu, diameter 1.3 to 1.9. In stagnant water, adherent to other vegetables. L. creespitosa, Ktz. Length 100 to 200 yw, diameter 2.4 to 2.8 4. Upon humid rocks. L. brevissima, Ktz. Length 75 to 100 yu, diameter 2.7 to 3.5 w. In stag- nant water. L. pusilla, Rabh. Length 60 to 70 yw, diameter 0.5 to 0.6 yu. LL. parasitica, Ktz. Length 90 to 150 yp, diameter 1 p. L. radians Ktz., and L. spissa, Rabh. Parasites upon marine alge. CLASSIFICATION OF THE BACTERIA. 91 g. Beggiatoa, Trev. Filaments very slender, surrounded by mucous mat- ter, rigid, having oscillatory movements. Protoplasm white, enclosing numerous granules, which recent observations have demonstrated to be crystalline sul- phur (Cramer, Cohn). The Beggiatoa are found most abundantly in thermal sulphur waters, where they constitute flocculi, which have been named Glairine, Baré- gine. They often live in water not containing free oxygen. They play a great réle in the elimination of sulphur and the disengagement of sulphuretted hydrogen in thermal waters. Their principal species are : — B. alba, Trev. A whitish mucous mass enclosing colorless filaments, having a diameter of 8.5 to 4 w. In most thermal and stagnant waters. B. arachnoidea, Rabh. Flocculi very minute, snow white, filaments as long as broad,—5.4 to 7 w. In the thermal waters of Europe. B. nivea, Rabh.; B. leptomitiformis, Trev., nearly related species, living in the same conditions. Cohn and Warming have also described : — B. mirabilis, Cohn, articles scarcely flexible, measuring 20 to 40 p. B. minima, Warming, a very small species, very flexible ; length 40 p, thickness 1.8 to 2 p. 4. SPIROBACTERIA. This tribe includes the bacteria with undulating filaments, or filaments in spirals, more or less de- \ pe ae Te 92 MORPHOLOGY OF THE BACTERIA. veloped, from the Vibrio rugula, which only pre- sents a single curve in its centre, to certain species of Spirillum which have numerous turns of the spiral. In several species, cilia, or a flagellum, have recently been observed. We divide them into three genera : — Fil. short, slightly sinuous . . . ViBrio. Fil. short, spiral, rigid . . . . SpIRILLUM. Fil. long, spiral, flexible. . . . SPIROCHATE. g. Vibrio, Auct. emend. Body filiform, more or less distinctly articu- lated, always undulating, having serpentine movements. This genus forms the transition between the Desmobacteria and Spirillum “from which it cannot be separated” (Warming). Fil. thick, with a single curve . . . V. RUGULA. Fil. slender, with several undulations . V. SERPENS. V. rugula, Miiller (V. lineola, Duj. ex parte). Filament presenting in its centre a single curva- ture, feeble but distinct; length 8 to 16 w. The shortest are slightly curved (= 6 w Warming), the larger, which may attain 17.6 » (Cohn), 35 w (Warm.), are about to divide. Movements of rotation more or less rapid around their longer axis; of progression forward, giving then the idea of a serpentine move- ment: having a cilium (Warming). V. rugula is commonly found in swarms, in infusions, in deposits upon the teeth, in intes- tinal matters (Leewenhoeck), in choleraic dis- charges (Pouchet). CLASSIFICATION OF THE BACTERIA. 93 V. serpens, Miiller. Filament one half less in diameter than the pre- ceding, rigid, annulate, having two or three regular undulations, at least two in the shortest; height of one turn of the undulations 8 to 12 yw, diameter 1 to 3 pw, total length 11 to 25 yw, thickness 0.7 4; move- ments analogous to those of B. subtilis ; having a cil- ium (Warm.). In numerous swarms in infusions, river water, etc. g. Spirochete, Ehrb. 8. plicatilis, Ehrb. Filament not extensible, twisted in a long helix, flexible, the turns of the spiral near together ; suscep- tible of twisting upon its axis and of an undulatory movement; total length 1380 to 200 yu. Rare species; in infusions, stagnant water, sea-water, etc. S. Obermeieri, Cohn. Does not differ from the preceding, either in size, conformation, or in its movements, but by its habitat and physiological peculiarities. In the blood of persons attacked by recurrent fever (Obermeier, 1872, Weigert, Bisch-Hirsch- feld, etc.) during the period of access, never during the remission. S. gigantea, Warming. Found upon the coasts of Den- mark; thickness of body, 3 p», height of spiral 25 mu, diam- eter 7 to 9 p. 94 MORPHOLOGY OF THE BACTERIA. g. Spirillum, Ehrb. Filament spiral, rigid; turns of spiral short and regular. S. tenue, Ehrb. Filament slightly tortuous, three to four turns of the spiral; length and diameter of a single turn, 2 to 3. When the filament has a turn and a half, it re- sembles an 2; the filaments of two to five turns have a length of 4 to 15 w; spiral movement very rapid. In infusions, etc. S. undula, Ehrb. (Vibrio prolifer, Ehrb.) Filament larger, turns of the spiral wider apart (from 3 to 5 w); having usually one half a turn to one full turn, rarely one and a half, two, or three; length 8 to 10 yu, breadth 5 yw, thickness of filament 1.8 w; having a very rapid spiral movement. Fetid animal and vegetable infusions and run- ning water. The S. rufum, Pertz only differs from this by its reddish color. 8. volutans, Ehrb. Filament large and thick, turns of spiral regular, well separated, and 13 w in height; number of turns two, three, and three and a half, rarely six and seven; total length 25 to 30 yw, thickness 1.5 uw, breadth 6.6 uw; movement sometimes rapid, sometimes motionless ; a well-defined cilium, already seen by Ehrenberg (Cohn, Warming). This giant of the bacteria is found in vege- table and animal infusions, in sea-water, and in fresh water. From Mier. Journ-Vol. -XIN,N 5S P1V AMetsel lth BBD ab Sore S STITT ST POL OTD) PLATE V. From “ Microscopical Journal.” Fic. 1.— Micrococcus prodigiosus (Monas prodigtosa, Ehr.). Spherical bacteria of the red pigment, aggregated in pairs and in fours; the other pigment bacteria are not distinguishable with the microscope from this one. Fie. 2.— Micrococcus vaccine. Spherical bacteria, from pock-lymph in a state of growth, aggregated in short four to eight-jointed straight or bent chains, and forming also irregular cell-masses. Fic. 8.— Zooglea-form of micrococcus, pellicles or mucous strata characterized by granule-like closely set spherules. Fie. 4.— Rosary chain (Torula-form) of Micrococcus uree, from the urine. Fig. 5. — Rosary-chain and yeast-like cell-masses from the white de- posit of a solution of sugar of milk which had become sour. Fie. 6.— Saccharomyces glutinis (Cryptococcus glutinis, Fersen.), a pullu- lating yeast which forms beautiful rose-colored patches on cooked potatoes. Fic. 7.— Sarcina spec,* from the blood of a healthy man,** from the surface of a hen’s egg grown over with Micrococcus luteus, forming yel- low patches. Fia. 8.— Bacterium termo, free motile form. Fie. 9.— Zooglea-form of Bacterium termo. Fic. 10. — Bacterium-pellicle, formed by rod-shaped bacteria arranged one against the other in a linear fashion, from the surface of sour beer. Fig. 11. — Bacterium lineola, free motile form. Fig. 12. — Zooglea-form of B. lineola. Fic. 13.— Motile filamentous Bacteria, with « spherical, or elliptical highly refringent “head,” perhaps developed from gonidia. i Fie. 14.— Bacillus subtilis, short cylinders and longer, very flexible motile filaments, some of which are in process of division. Fig. 15. — Bacillus ulna, single segments and longer threads, some breaking up into segments. Fie. 16.— Vibrio rugula, single or in process of division. Fia. 17. —Vibrio serpens, longer or shorter threads, some dividing into bits, at * two threads entwined. Fig. 18.—‘ Swarm ” of V. serpens, the threads felted. Fie. 19. — Spirillum tenue, single and felted into “ swarms.” Fie. 20. — Spirillum undula. Fia. 21. — Spirillum volutans,* two spirals twisted around one another. Fic. 22. — Spirocheete plicatilis. All the figures were drawn by Dr. Ferdinand Cohn with the immersion lens No. IX. of Hartnack Ocular III., representing a magnifying power of 650 diameters. 96 MORPHOLOGY OF THE BACTERIA. M. Warming has recently described three new species found upon the coast of Denmark : — Sp. violaceum, height 8 to 10 p, diameter 1 to 1.5 p, thick- ness 8 to 4»; a cilium at each extremity. Sp. Rosenbergit, height of helix 6 to 7.5 p, thickness 1.5 to 2.6 p. Sp. attenuatum, body very attenuated at the two extrem- ities, without a cilium. We give below some details concerning the other colorless Schizophytes : — . Sarcina, Goods. The Sarcina, which it is useless to describe here, can be considered as bacteria in which the division occurs by two perpendicular par- titions in such a manner that multiplication takes place in two directions. Sarcina is very nearly allied to Merismopedia, from which it only differs by the absence of chlorophyll ; its siliceous skeleton allies it with the diatoms. . Ascococeus, Billr. Cells hyaline, small, globular, closely united in globular or oval families, irregularly lobed and lobu- lated, surrounded by a thick gelatinous envelope, cartilaginous, forming a soft membrane, flaky, easily separating. . Billrothi, Cohn. Families in masses of 20 to 160 p, surrounded by a thick membrane of 15 p. In a solution of tartaric acid exposed to the air. . Myconostoc, Cohn. Filaments very slender, colorless, folded, rolled up in a mucous substance, united in very smal] globules. CLASSIFICATION OF THE BACTERIA. 97 M. gregarium, Cohn. Unique species found on the surface of a putrefying infusion. g. Cladothriz, Cohn. Filaments in form of leptothriz, very slender, color- less, not articulated, rigid or a little undulating, falsely dichotomous. Cl. dichotoma, Cohn. In foul water. g. Streptothriz, Cohn. Filaments in form of leptothriz, very slender, color- less, not articulated, straight or slightly spiral, a little branched. Str. Fersteri, Cohn. In concretions in the lachrymal canal of man. PLATE VI. From photo-micrographs made in Havana and New Orleans. Re- produced by permission of the National Board of Health. Fic. 1.— Spirochete (plicatile?). From foul bilge-water, Hav- ana, Sept. 1879. Xx 1,450 by Zeiss’s , in. objective. Fic. 2. — Vibrios from water of harbor, Havana, near discharge of sewer, Aug., 1879. > 1,450 diameters by Zeiss’s yy in. objective. Fig. 8. — Sarcina (sp. ?). From standing water in flower-vase, Lafayette cemetery, New Orleans, April, 1880. > 400 diameters by Beck’s } in. objective. Fie. 4.— Spirillum (volutans ?). From foul gutter-water, New Orleans, May, 1880. > 600 diameters. PLATE VIL PART SECOND. PHYSIOLOGY OF THE BACTERIA. CHAPTER I. DEVELOPMENT OF THE BACTERIA. Tue bacteria are now known to us from a mor- phological point of view: let us proceed to study the life of these microscopic beings; first, from a general point of view, that is to say, by study- ing their functions of nutrition and reproduction, independently of the special characters impressed upon these functions by certain media; then by considering the relations which are established between the bacteria and the particular media in which they may be developed. The bacteria are of all beings the most widely diffused. We meet them everywhere, — in the air, in water, upon the surface of solid bodies, in the interior of plants and animals. If we expose a transparent liquid containing traces of. organic substances, we find after a short time that it has become clouded, and the microscope shows us that it contains myriads of these beings. What is the source of these organisms so widely disseminated, and which develop so rapidly? This PLATE VII. DISSEMINATION OF THE BACTERIA, From photo-micrographs made in New Orleans. Copied by permission of the National Board of Health. Fie. 1.— Spirillum (Sp.?) from water of salt marsh, near Salem, Mass. X 400 diameters by Beck’s 4 in. objective. Fie. 2. — Bacteria in distilled water (see note on page 107). X 1,000 diameters by Zeiss’s J, in. objective. Fig. 3. — Leptothrix buccalis, epithelial cell, etc., from human mouth. X 1,000 diameters by Zeiss’s ~, in. objective. Fia. 4.— Bacteria from human foeces. > 1,500 diameters by Zeiss’s jy in. objective. PEATE VIL. . , ee ‘ oJ ta). “4% ne ae ’ -* "Ve “yy i. ig DEVELOPMENT OF THE BACTERIA. 101 is the first question which presents itself,—a ques- tion which has given rise to long discussions, in the examination of which we shall only enter in order to give a short historical statement. § 1.— OriGIN OF THE BACTERIA. The origin of the bacteria, as of all the other inferior organisms, is conceived in three different manners : — 1. For some, these organisms are produced by heterogenesis ; that is to say, by creation outright from mineral or organic substances (spontaneous generation). 2. According to others, they come directly from individuals like themselves, by one of the known modes of generation, — fission, spores, etc. 3. Finally it is believed that they are derived from organisms already existing, and are nothing more than different states or phases of develop- ment of known species, of which the life cycle is not yet discovered. We will examine the latter hypothesis, which constitutes what is called polymorphism, when we speak of the phenomena of reproduction. ‘As to the two first, we will content ourselves with indicating the late works which have appeared for and against each; insisting above all upon the facts which relate to the proof of the presence of bacteria or their germs in the air, water, and liquids or tissues of the human organism, — blood, urine, etc. 102 PHYSIOLOGY OF THE BACTERIA. Heterogenesis. — Since the experiments of Pou- chet and of his pupils, and the arguments given by MM. Trécul and Frémy, the last facts invoked in favor of heterogenesis are due to MM. Onimus, Servel, Bastian, etc. M. Onimus contends that the “ proto-organisms may be born in media, protected against the air, which contain albuminoid substances.” M. Martin sustains an analogous idea. Accord- ing to him, the bacteria are derived from protein granules. According to Neusch, bacteria are pro- duced in the interior of animal or vegetable cells without any lesion and without coming from the air. To demonstrate this he plunges divers fruits under water, in saline or acid liquids (phosphates, sulphates, carbonate of potassa, etc.),and he finds there bacteria; but, according to him, these are not living organisms, properly so called, but ab- normal cellular vegetations. M. Servel, decapitating some guinea-pigs, caused the heads, the livers, and the kidneys to fall into a solution of chromic acid, 1 to 100. At the end of several days, the superficial parts were hard- ened; but the centre was softened, and filled with bacteria. The presence of bacteria in eggs has several times been verified, and the heterogenists have hastened to draw an argument from this fact in favor of their theory. M. Gayon explains the ap- pearance of these organisms in the eggs of birds by their -presence in the normal state in the oviducts. DEVELOPMENT OF THE BACTERIA. 103 Finally, Bastian, having succeeded in obtaining bacteria in liquids which he believes deprived of every germ, believes in their spontaneous genera- tion. The following is a réswmé of his experiment : Normal acid urine is brought to the boiling- point, then a solution of potash (in sufficient quan- tity to neutralize the volume of urine employed) is also brought to the boiling-point ; after cooling, the two liquids are mixed, and the whole placed in an oven at 50°. At the end of two or three days, bacteria are developed. Pasteur points out three causes of error in the experiment of Bastian: 1. The germs may come from the urine; 2. The germs may come from the solution of potash; 8. The germs may be fur- nished by the vessels employed in the experiment. In support of this criticism, Pasteur has made some similar experiments, guarding against these causes of error, and has not obtained bacteria. DISSEMINATION OF BACTERTA IN AIR AND WATER. Air. — The experiment of Pasteur for gathering atmospheric germs is well known. He fixes a glass tube in an aperture made in a window-blind. The extremity of the tube, which communicates with the open air, is closed with a plug of cotton, to the other extremity is attached an aspirator. When the air has filtered through the cotton for some hours, this is examined, and is found to be filled with germs. 104 PHYSIOLOGY OF THE BACTERIA. Before Pasteur, Ehrenberg and G. de Claubry had already announced the presence in the air of the eggs of infusoria. Robin had also recognized that the atmosphere contains, in addition to all sorts of débris,.spores, pollen-grains, portions of insects, and rarely the eggs of. infusoria. More recently Maddox and Cunningham, by the aid of an aeroscope invented by the former, gathered numerous microbes, as well as bacteroid particles. Tyndall, by causing a ray of light to enter a dark- ened chamber, has rendered visible all these mi- nute corpuscles. His researches show that the optical examination of air enables us to determine in an exact manner the presence or absence of germs. Let us also mention the experiments recently made by Miquel in the park of Montsouris. This observer has found in the atmosphere a consider- able number of germs. For the forms of which the diameter exceeds 2 uw, he has ascertained that “the average number of microbes in the air is feeble in winter and augments rapidly in spring, etc.; 2. That rain always diminishes the number of these microbes; 3. That rain-water introduced with the greatest precautions, into flasks with slen- der curved necks, first heated to destroy germs, rarely contains rotifers, etc., but always contains bacteria.” En résumé, the existence of germs can be dem- onstrated, 1, by direct research ; and 2, by cultiva- tion. Direct research may be made by the optical examination of the air (method of Tyndall), the DEVELOPMENT OF THE BACTERIA. 105 microscopic examination of dust (method followed by Marié-Davy, Tissandier), the examination of particles obtained by filtration, by gathering germs with an aeroscope, by condensation of atmospheric moisture upon refrigerating vases, etc. The culti- vations consist in exposing to the air which is to be examined some liquids in which all pre-existing germs have been destroyed (Pasteur, Tyndall, etc.). This method has shown that liquids exposed in an atmosphere deprived of all germs does not undergo putrefaction, but this occurs as soon as the access of air not deprived of germs is per- mitted (Tyndall). All of these methods give concordant results ; deposits containing germs of various kinds are always obtained. But this objection presents itself to the mind: Do the bacteria obtained by cultiva- tion exist in the atmosphere? or do they come from germs which have developed rapidly upon finding a favorable medium? From the experi- ments of Cohn, Miquel, etc., it is known that the atmosphere contains very few adult bacteria. Mi- quel in a recent communication says, in effect, that bacteria are rarely found in the air in a complete state, but rather under the form of shining points, difficult to distinguish directly one species from another. Are not these brilliant points Micrococci? In other terms, the air contains permanent spores, organisms which, as we shall see in speaking of the reproduction of the bacteria, develop at a certain period of the existence of the adult forms, in their interior, which escape from the sporogenous fila- 106 PHYSIOLOGY OF THE BACTERIA. ment, are drawn into the air by the evaporation of the liquid containing them, or, after dessication, by the winds. These spores are the point of depart- ure of epidemic foci, and their extreme lightness explains how readily they are’ disseminated by the winds. . Water. — Water contains considerable quantities of bacteria and especially of germs. Their pres- ence in atmospheric water is established by the experiments of Lemaire and Gratiolet, — and after them by more recent observers, — by means of con- densers filled with ice, and placed in the fields and for comparison in closed apartments. Rindfleisch has since expressed the opinion that the vapor of water does not contain spores or bacteria, and that telluric waters alone contain them; but Billroth, Cohn, and others have proved that Rindfleisch was too positive in his statement. It is not surprising that telluric waters contain such a quantity of bacteria that their existence is admitted by all. The dust gathered upon the sur- face of stones, of leaves, of fruits, etc., shows upon microscopic examination an abundance of germs (Marié-Davy, Tissander); the washing of these objects and of the soil by the rain transports them into the rivers and from the rivers to the sea, which contains considerable quantities of them. Thus, a drop of water from the Seine, according to Pasteur and Joubert, is always fecund, and may give birth to several species of bacteria. The dis- tilled water of laboratories also contains germs, and DEVELOPMENT OF THE BACTERIA. 107 these of so small a diameter that they pass through all filters! Cohn has proved that some are not arrested by a super position of sixteen filters. The only waters which do not contain them are those drawn from the very source of a spring. DISSEMINATION OF BACTERIA IN THE HUMAN ORGANISM. If bacteria are so generally disseminated in the great external media, it is not surprising that they are found on the surface of the human body and in the interior of the organs in communication with the exterior. But to account for their pres- ence in the interior of organs we find ourselves in presence of two hypotheses: one admitting the spontaneous production of these organisms in the interior of the tissues, the second explaining it by the introduction through the membranes of the germs of bacteria from without. 1 Having been directed by the National Board of Health’ to make some experiments with a view to confirming or disproving the results of Klebs and Crudelli, who claim to have found the germ of malarial fevers in the atmosphere of the Pontine marshes near Rome (their Bacillus ma- lari), I aspirated ten gallons of air on the edge of a swamp in the vicin- ity of New Orleans, through 4 c.c. of distilled water. Upon examining this water with the microscope on the following morning, I was surprised to find a large number of actively moving bacteria and monads (Afonas lens). To make sure that these really came from the air, I examined my distilled water, which had been standing in the laboratory for several weeks (in a bottle, corked, but occasionally opened as distilled water was required) and found the same forms present in considerable numbers, not so numerous, however, as in the water through which swamp air had been drawn. As the germs were present in the distilled water, I presume that the passing of air through it for several hours, and the organic matter contained in it, favored the development and multiplication of these micro-organisms. Subsequent experiments with freshly distilled water gave very different results as to the number of organisms found. See fig. 2, plate vii—G, M. S. 108 PHYSIOLOGY OF THE BACTERIA. In truth, the cutaneous surfaces are penetrated with difficulty by germs, although the hairs upon the surface of the body serve to collect them. The short hairs in the nares prevent, to some ex- tent, the atmospheric germs from penetrating into the bronchi, but this protection is not sufficient ; and, notwithstanding the mucus of the nasal fossee and of the pharynx, they may be found in the al- veoli of the lungs, if we may believe Rindfleisch and Eberth. Do the bacteria pass into the blood ? They may be transported in food and drink into the alimentary canal, where an elevated tempera- ture, the presence of saliva, etc., favor their de- — velopment. On the other hand, the acid secretions of the stomach, the bile, and the pancreatic juice moderate, if they do not prevent, the multiplica- tion of these organisms. The presence of bacteria in normal blood and urine, or their occasional entrance into these fluids, are lmportant questions, which have induced many contradictory researches, but which are not yet definitely settled.’ 1 “If there is any organism in the blood of yellow-fever demon- strable by the highest powers of the microscope as at present perfected, the photo-micrographs taken in Havana should show it. No such organ- ism is shown in any preparation photographed immediately after collection. But in certain specimens kept under observation in culture cells, hyphomy- cetous fungi and spherical bacteria made their appearance after an inter- val of from one to seven days. The appearance of these organisms was, however, exceptional; and in several specimens taken from the same individual at the same time, it occurred that in one or two a certain fun- gus made its appearance, and in others it did not. This fact shows that the method employed cannot be depended upon for the exclusion of atmos- pheric germs, but does not affect the value of the result in the consider- able number of instances in which no development of organisms occurred DEVELOPMENT OF THE BACTERIA. 109 Two kinds of researches have been undertaken for the purpose of discovering germs in normal blood. The direct method, or microscopic exam- ination, has given results very much disputed. The blood contains, indeed, a considerable number of little granules, of which the nature is doubtful, and which it is difficult to distinguish from Micro- coccus. Thus, while Liiders asserts that normal blood contains germs, or spores, which only await a favorable alteration in the fluid in order to de- velop themselves, Rindfleisch formally denies their existence. The indirect method, which consists in cultivat- in culture cells in which blood, in a moist state was kept under daily observation for a week or more. “The method employed seemed the only one practicable for obtaining blood from a large number of individuals without inflicting unwdrrant- able pain and disturbance upon the sick. It was as follows: One of the patient’s fingers was carefully washed with a wet towel (wet sometimes with alcohol and at others with water), and a puncture was made just back of the matrix of the nail with a small triangular-pointed trovar from hypodermic syringe case. As quickly as possible a number of thin glass covers were applied to the drop of blood which flowed. And these were then inverted over shallow cells in clean glass slips, being attached usually by a circle of white zinc cement. In dry preparations, which are most suitable for photography, the small drop of blood was spread upon the thin glass cover by means of the end of a glass slip. “The thin glass covers were taken from a bottle of alcohol, and cleaned immediately before using; and usually the glass slips were heated shortly before applying the covers, for the purpose of destroying any atmospheric germs which might have lodged upon them. These precautions were not, however, sufficient to prevent the inoculation of certain specimens by germs floating in the atmosphere (Penicillium and micrococct) ; and in nearly every specimen the presence of epithelial cells, and occasionally a fibre of cotton or linen, gave evidence that under the circumstances such contamination was unavoidable. It is therefore be- lieved that any organism developing in the blood of yellow-fever, or of other diseases collected by the method described, or by any similar method, can have no great significance, unless it is found to develop as a rule (not occasionally) in the blood of patients suffering from the dis- 110 PHYSIOLOGY OF THE BACTERIA. ing normal blood in flasks perfectly closed, has also given some favorable results, such as those of Hensen, Tiegel, Billroth, and Nedvedsky, and some unfavorable results, as those of Liiders and Pasteur. According to Nedvedsky, the blood “ con- tains germs capable of undergoing in it, under certain circumstances, an ulterior development: these are the Hémococcos.” If these germs do not give birth, normally, to bacteria, it is because the blood is as injurious to them as the most advanced stages of putrefaction (Billroth). If this hypoth- esis is true, it explains several embarrassing facts, such as the existence of micrococci in the pus of ease in question, and is proved by comparative tests not to develop in the blood of healthy individuals, obtained at the same time and by the same method. “ Tried by this test, it must be admitted that certain fungi and groups of micrococci, shown in photographs taken from specimens of yellow- fever blood collected at the military hospital and preserved in culture cells, cannot reasonably be supposed to be peculiar to or to have any causal relation to this disease.” — Preliminary Report of Havana Commis- sion to National Board of Health. In subsequent observations upon the blood of malarial fever, of syphilis, and of leprosy, I have sometimes obtained a development of micrococci in culture cells where all possible precautions as to the exclu- sion of atmospheric germs had been taken, and in one case have seen the development of Penicillium in another of Sarcina. The last observa- tion is, so far as I know unique, and I have still in my possession the culture-slide containing numerous masses of Sarcina, presenting the characteristic arrangement of the cells in fours. This slide was put up at the bedside of a patient suffering from intermittent fever in the Char- ity Hospital, New Orleans. Every precaution was taken to exclude at- mospheric germs. The patient’s finger was washed with absolute alcohol just before making the puncture from which the little drop of blood was obtained. The question as to whether in this and similar cases the germs of the organism which develops come from the atmosphere or pre-existed in the blood is one to which I propose to give special atten- tion ; and, after further experiment, I shall discuss it in my report to the National Board of Health. — G. M. 8. DEVELOPMENT OF THE BACTERIA. 111 closed abcesses, in cysts, in urine drawn from the bladder, etc. § 2.—NuTRITION AND RESPIRATION OF THE , BACTERIA. The bacteria, being organisms composed of a cell membrane of cellulose, and of protoplasmic contents, deprived of chlorophyll, must receive nutriment and respire in the same manner as all the colorless vegetables and all the inferior animals deprived of special apparatus, — that is to say, by endosmotic absorption. Although the media in which the bacteria de- velop are various, yet, from the point of view of the nutritive function, they act everywhere ac- cording to the same laws. No matter in what medium they live, they must have water, nitro- gen, carbon, and oxygen, as well as certain min- eral salts which enter, but in quantities exceedingly minute, into the chemical constitution of all organ- ized bodies. Water. — This element is indispensable to the active life and development of the bacteria. Dessi- cation arrests completely the movements of those which are mobile, and the functions of all the bacteria in general; but it does not kill them, at least if it be not prolonged beyond a certain time. The Micrococci of different kinds of virus are examples of the continued vitality of these organisms after dessication for a considerable time. 112 PHYSIOLOGY OF THE BACTERIA. The bacteria present in this respect numerous va- riations according to the species and the period of development which they have attained. In the state of permanent spores, they are extremely ten- acious of vitality. They resist for a long time not only dessication, but a considerable elevation of temperature. Among the bacteria, some are developed in liq- uids,— the greater number, — others upon damp surfaces. The former can live in fresh water, sea- water, thermal waters, and the liquids of animal or vegetable organisms, etc. A surprising fact is, that the composition, so different, of fresh and sea water appears to have no influence upon the bacteria. We find in both all the species, from Bacterium termo to Spirillum volutans. Nitrogen. — Pasteur has demonstrated that it is not necessary that the nitrogen which is to serve as nutriment to the bacteria should be in the form of albumen, but that these organisms can take posses- sion of it in the form of ammonia. In fact, in Pasteur’s solution, composed as fol- lows : — Distilled water . . . . . . 100. Sugarcandy. ...... 10. Tartrate of ammonia . . . . 1. Ashes of one gramme of yeast . 0.075. the bacteria increase sometimes with such rapidity that they interfere with the development of the alcoholic ferment. DEVELOPMENT OF THE BACTERIA. 113 Cohn, in order to better observe the phenomena and to get rid of the moulds, which the cane-sugar caused to develop too rapidly, employed the fol- lowing culture-fluid : — Distilled water . . . . 100. Tartrate of ammonia . . 1. Ashes of yeast . . . .. 1. Bacteria develop in this fluid wonderfully, which proves that sugar is not indispensable to them. One other solution often employed is that of Mayer. It has the advantage of not requiring the employment of ashes of yeast: — Phosphate of potash . . . 0.1 gramme. Sulphate of magnesia. . . O01 4, Tribasic phosphate of lime . 0.1 ,, Distilled water . . . . . 20 cc. Cohn adds to this 0.2 gr. tartrate of ammonia. En, résumé, the bacteria can take nitrogen, which they need in order to form their protoplasm, either from albuminous compounds, which they decom- pose, as in putrefaction, or in the form of am- monia, or, perhaps, by borrowing it from nitric acid, but this last source is not well established (Cohn). Carbon.—In addition to the sources common to other organisms, the bacteria can take this im- portant element of their composition, under cer- tain circumstances, from the organic acids. Thus, when we cultivate bacteria in a solution containing 8 114 PHYSIOLOGY OF THE BACTERIA. only tartrate of ammonia with a small quantity of mineral salts (phosphoric acid, potash, sulphuric acid, lime, and magnesia), they develop rapidly, taking their carbon from the tartaric acid. i Cohn has endeavored to ascertain if other or- ganic acids could be assimilated by the bacteria. By making use of succinate of ammonia, or neutral acetate of ammonia, he has been able to cultivate these microphytes. Besides, as Pasteur had already experimented with solutions containing lactates, and in which bacteria had developed until the salt had completely disappeared, we may admit that the bacteria can assimilate the organic acids, — tartaric, succinic, acetic, and lactic; but tartaric acid seems to furnish the best alimentary solution. Other substances containing carbon are also as- similated by the bacteria,—cane-sugar, milk-sugar, glycerine, and even cellulose (according to Mit- scherlich). Cohn concludes, “ that the bacteria multiply quite normally, and in great quantity, whenever they find the elements in solution which constitute ashes, and that they can take the carbon which they need from any organic substance containing it, and their nitrogen from ammonia, urea, and probably from nitric acid. The bacteria, then, re- semble green plants, in that they assimilate nitro- gen contained in their cells by taking it from ammonia compounds, which animals cannot do. They differ from green plants in that they cannot draw their carbon from carbonic acid, and only assimilate organic substances containing carbon, DEVELOPMENT OF THE BACTERIA. 115 above all the hydrates of carbon and their deriv- atives; and in this respect they resemble animals.” Absorption. — How are these various substances absorbed? The observations of Grimm, Hoffmann, de Seynes, etc., permit us to assure ourselves that these organisms absorb by endosmosis the sub- stances upon which they are nourished. Grimm, upon examining with the microscope some particles of lemon containing bacteria and spores of alge, saw a certain number of the former gather around a spore, and fix themselves to it by one of their extremities. They did not pene- trate it; but when they abandoned it, the spore had diminished in volume, and lost a portion of its contents, while the bacteria had taken a greenish color. Hoffmann has seen that these little organisms, when placed in a solution of carmine or of fu- schine, after a time are colored an intense red, while the mucus surrounding them remains color- less. De Seynes, also, from his observations upon the vibrios which accompanied some colored fila- ments of Penicillium glaucum, believes that bacte- ria are susceptible of absorbing coloring matters from vegetables and from animals with which they are in contact. Oxygen. — The réle of oxygen in the life of the bacteria has given rise to numerous controversies. First, it seems a priori that the bacteria ought 116 PHYSIOLOGY OF THE BACTERIA. to act like all other living beings, and to respire like the other inferior organisms deprived of chlo- rophyll — that is to say by absorbing oxygen and eliminating carbonic acid. This is, indeed, the opinion of a great number of botanists. But, according to Pasteur, it is not so with the bacteria. When we examine what occurs in putrefaction, we find that at first certain species are developed (Monas crepusculum, Bacterium termo, etc.), which absorb all the oxygen dissolved in the liquid, and come to the surface where they form a thick veil; after this, other species of vibrioniens appear, which are developed in a medium entirely de- prived of free oxygen, by borrowing this gas from the fermentable matters contained in the liquid. These chemical decompositions constitute putrefaction. The first of these organisms, regarding the na- ture of which Pasteur has long been uncertain, are aérobies : they live in contact with the air, and have need of oxygen. The second, anaérobies, not only have no need of oxygen, but are killed by it. These differences in the respiration of organ- isms belonging to the same group are not admitted by a great number of recent observers. Hoff- mann, among others, says expressly: “ These little beings cannot live without air, I should say with- out oxygen: if this gas is wanting, they cease to move and do not multiply at all. If a drop of liquid full of bacteria is placed upon a glass slip, then covered by a piece of thin glass, the active DEVELOPMENT OF THE BACTERIA. 117 bacteria will all approach gradually to the margins of the cover; and it is there that at the end of several days, after the successive death of the greater number, some are still found endowed with life and movement. If a similar preparation is at the same time protected by an impermeable ce- ment against dessication and against the introduc- tion of atmospheric air, all movement among the bacteria will cease at the end of two minutes, pro- vided, however, that no air bubble has been im- prisoned with the liquid.” The influence of oxygen upon the life and de- velopment of bacteria is also very manifest in an experiment recently made, and not yet published, by Toussaint, who has been kind enough to com- municate it to me. In studying the development of the spores of Bacillus anthracis in the moist chamber of Ranvier, Toussaint has observed the following curious facts, which offer a striking analogy to those above mentioned, borrowed from Hoff- mann, “The bacteria, which occupy the cen- tral portion of the moist chamber and which by reason of their situation receive very little oxygen from the groove, are soon arrested in their development; while those which occupy the borders are long and heaped up in immense num- bers, those in the centre remain small, formed of two, four, or five articles, which are easily sepa- rated from each other; they soon cease to grow and are not transformed into spores.” Cohn is also as explicit. “There is no doubt,” 118 PHYSIOLOGY OF THE BACTERIA. he says, “that the complete development of Bacil- lus, and above all reproduction by means of spores, is only made under the influence of free access of air.” We might explain the contradictory facts of Pasteur by admitting, with Cohn, that the appear- ance of different réles played by the aérobies (Bacterium) and the anaérobies (Bacillus) is sim- ply due to a veritable struggle for existence which takes place between the microbacteria and the desmobacteria. ACTION OF VARIOUS AGENTS UPON THE BACTERIA. In this paragraph I shall pass in review the action of temperature, of movement, and of va- rious antiseptics. Temperature. —It is very important to study the manner in which bacteria comport themselves under extreme variations of temperature. It is, indeed, upon the results furnished by these re- searches that a great part of the arguments op- posed to the panspermatists by the heterogenists are based. We shall consider the influence upon bacteria of moderate temperatures and of extremes above and below zero. Moderate temperatures— that is to say those which are comprised between 25 and 40° (77 to 104° Fah.) — are generally favorable. The most favorable has been found to be 35° (95° Fah.) (Onimus). DEVELOPMENT OF THE BACTERIA. 119 The degree of resistance to extreme tempera- tures is very variable, according to the species. Thus, according to Frisch, a temperature of 45 to 50° (113 to 122° Fah.) is sufficient to kill B. termo, whilst 80° (176° Fah.) does not kill the “ Bactéri- dies” (Bacillus). The permanent spores are especially remarkable by the tolerance which they possess for high tem- peratures. They have been subjected to 100° (212° Fah.) (Schwann), 110° (Pasteur) and even 130° (Schrader) without losing their power of germinating. We must, however, recognize that the results of the experimenters offer the greatest diversity, the result, according to Cohn, of the difficulty of obtaining an equable distribution of the heat in the media, which are generally bad conductors. Cohn has arrived at the following conclusions as the result of numerous experiments made upon the Bacillus of hay infusions : — 1. At a temperature of 45 to 50°(113 to 122° Fah.) the Bacillus still multiplies rapidly, and forms as usual membranes and spores, while the other schizophytes existing in the infusion of hay are at this temperature incapable of multi- plication. 2. Ata temperature of 50 to 55° (122 to 131° Fah.) all reproduction and development of Bacillus ceases. It neither forms pellicles or spores; the filaments are killed, the spores, on the contrary, preserve, for a longer time (for at least seventeen hours) the property of germinating. 120 PHYSIOLOGY OF THE BACTERIA. 3. While infusions of hay are generally sterilized by a temperature of 60° (140° Fah.) or more, pro- longed during twenty-four hours, certain spores of: Bacillus seem able to endure a temperature of 70 to 80° (158 to 176° Fah.) during three or four days without losing the power of germinating. By some experiments made with refrigerating mixtures, Cohn has ascertained that the bacteria are not killed by very low temperatures, acting even during several hours,— 18° for example (0° Fah.). But they are benumbed at a tempera- ture of i (32° Fah.) and probably at a temperature a little higher, losing the power of movement and of reproduction, and consequently their action as ferments. They preserve, however, their capacity to resume their activity at a more elevated tem- perature. Frisch has pushed the experiment still further than Cohn. By the evaporation of carbonic acid, he has produced as low a temperature as — 87° (— 123° Fah.) in liquids containing bacteria, with- out destroying the vitality of these organisms, development having subsequently occurred of coc- cos and of bacteria. Congelation, then, cannot serve to destroy the organized ferments. Let us add, however, that if the passage to ex- treme temperatures is too sudden, there is then an alteration (destruction ?) of these organisms (Schu- macher). Movement.— We would not have consecrated a paragraph to the action of movement upon DEVELOPMENT OF THE BACTERIA. 121 bacteria, if Crova had not recently asserted that movements impressed upon a liquid containing bacteria completely arrests their development. This is an assertion in complete opposition to all that we know of the physiology of these organ- isms, and which it is difficult to reconcile with the fact that bacteria may develop even in the torrent of the circulation. Compressed Air. — We have just seen the in- fluence of air, and especially of oxygen, upon the bacteria. When this agent is in a certain state of tension, it acts in a different manner. M. Paul Bert has proved that under a tension of twenty- three to twenty-four atmospheres all the putrefac- tive processes depending upon the development of vibrios cease to occur. Since, the same savant has found that the anatomical elements and even the red blood globules are killed by oxygen. These researches agree well enough with those of Grossmann and Mayerhauser upon the life of bacteria in gas. From their numerous experi- ments it appears that, under the influence of oxy- gen, there is an exaggeration of the activity of the bacteria; but if the oxygen is under a pres- sure of five to seven atmospheres, the bacteria live from six to twenty hours, then die, and cannot be resuscitated by atmospheric air. Ozone causes a definite and almost instantaneous arrest of movement. 122 PHYSIOLOGY OF THE BACTERIA. Other gases studied by the same savants have given the following results: — Hydrogen at first causes an acceleration of movement, which is maintained for several days ; then movement becomes less active, and finally it ceases altogether. Carbonic Acid.— Contrary to the facts stated by Pasteur, this agent was found to paralyze the bacteria, and reduced them to complete immobility. If the carbonic acid is displaced by oxygen, the bacteria resume their activity. Chloroform. — This substance, according to the researches of Miintz, arrests the vital phenomena of organized ferments. Miintz uses this charac- ter in order to recognize the soluble ferments, upon which it has no action. Boracic Acid.—Since the labors of Dumas, which have demonstrated that boracic acid kills the inferior organisms by depriving them of their oxygen, this substance has been employed in vari- ous circumstances as an antiseptic. Sulphate of Quinine. — The action of quinine, either in the state of chlorhydrate or of sulphate, is not yet well established. The experiments of Binz, Manassein, Kroevitsch, Bochefontaine, etc., have, in truth, given contradictory results. Carbolic Acid.—The experiments of Manas- sein have demonstrated that jth per cent of car- DEVELOPMENT OF THE BACTERIA. 123 bolic acid is sufficient to prevent all development of living beings. It is employed with success in anthrax, in the treatment of wounds, etc. § 3.— REPRODUCTION OF THE BAcTERIA. It is well established that the bacteria can mul- tiply by fission, and reproduce themselves also by the formation of endogenous spores. Fission. — The multiplication by fission consists in a transverse division of the cell. When a bac- terium has attained nearly double its ordinary length, we see, in the larger species, that the proto- plasm becomes clearer in the central portion, and a partition forms in the median line separating the contained protoplasm into two portions. The par- tition, at first very delicate, becomes thicker, di- vides into two, and the two articles separate. This phenomenon is produced more or less quickly according to the nature of the medium, its richness in nutritive material, the temperature, etc. When the growth is rapid, the new cells form more quickly than they separate, and are arranged in chaplets. Very often we only find them in this form, in strings of two to four cells coupled together. In some forms the transverse division is preceded by constriction near the middle of the cell. Before the two new cells are separated, the bacterium in this case presents the appearance of a figure 8, and seems to be a simple cell swollen at the two extremities. 124 PHYSIOLOGY OF THE BACTERIA. Under other circumstances, and probably in con- sequence of a mucus transformation of the walls of the mother cells, the new bacteria are envel- oped by a mass of glutinous substance. We have described these masses under the name of Zo- oglea. The conditions which favor multiplication by fission are, a certain degree of temperature and a sufficient quantity of nutritive material. The higher the temperature, the more rapid is the . segmentation of the bacteria, the more rapid their multiplication, — that is to say, up to a certain limit, variable with the species and beyond which the bacteria are destroyed. The multiplication decreases when the tempera- ture is lower, and ceases entirely in the vicinity of 0° (82° Fah.). The influence of richness of nutriment is well seen in artificial cultivation. So long as the bacte- ria find the necessary aliment, in sufficient quantity, to form new protoplasm, they multiply with ac- tivity; but as soon as the organic matter is de- voured, they cease to divide, fall to the bottom of the vessel, where they accumulate, motionless, and form a deposit more or less abundant. The multiplication of the bacteria by binary fis- sion has for result, if nothing occurs to interfere with the most favorable conditions, the invasion of the medium by an incredible number of these little beings, of which we can only form an idea by calculation. “ Let us suppose,” says Cohn, “ that a bacterium DEVELOPMENT OF THE BACTERIA. 125 divides into two in the space of an hour, then in four at the end of a second hour, then in eight at the end of three hours, in twenty-four hours the number will already amount to more than six- teen millions and a half (16,777,220); at the end of two days this bacterium will have multiplied to the incredible number of 281,500,000,000; at the end of three days it will have furnished forty- seven trillions; at the end of about a week, a number which can only be represented by fifty-one figures. “In order to render these numbers more com- prehensible, let us seek the volume and the weight which may result from the multiplication of a single bacterium. The individuals of the most cominon species of rod-bacteria present the form of a short cylinder having a diameter of a thou- sandth of a millimeter, and in the vicinity of one five hundredth of a millimetre in length. Let us rep- resent to ourselves a cubic measure of a millimetre. This measure would contain, according to what we have just said, 633,000,000 of rod-bacteria with- out leaving any empty space. Now, at the end of twenty-four hours the bacteria coming from a single rod would occupy the fortieth part of a cubic millimeter; but at the end of the follow- ing day they would fill a space equal to 442,570 of these cubes, or about a half a litre. Let us admit that the space occupied by the sea is equal to two-thirds of the terrestrial surface, and that its mean depth is a mile, the capacity of the ocean will be 928,000,000 of cubic miles. The multipli- 126 PHYSIOLOGY OF THE BACTERIA. cation being continued with the same conditions, the bacteria issuing from a single germ would fill the ocean in five days.” Reproduction by Spores.—The multiplication by fission, known to the earliest microscopists, has been until recently the only mode of propagation admitted by the authors. Thus M. de Lanessan, in the excellent article which he has devoted to the bacteria, says that the marvellous resources -of modern science have not yet permitted us to rec- ognize any other mode of propagation for these organisms. However, M. Ch. Robin had already, in 1853, indicated the presence in Leptothriz buccalis of little round bodies, “which are perhaps spores.” Pasteur has since, in 1865, recognized that “ the vibrios of putrefaction and of butyric fermentation present a sort of ovule, or ovoid corpuscle, which refracts light strongly, either in the extremity or in the body of the articles.” Later, the same savant, more explicitly, says clearly that these or- ganisms have two modes of reproduction, — by fission and by interior spores (“noyaux’’). Towards the same epoch, Hoffmann also pointed out a reproduction by free cellular formation in some bacteria. But we must come to the labors of Cohn, Billroth, and Koch, in order to find pre- cise observations in this regard. The formation of spores has been observed in Bacillus subtilis by Cohn, Bacillus anthracis by Koch, and in Bacillus Amylobacter by Van Tieghem. PLATE VIII. 1. Fic. Fic. PLATE VIII. ForMATION oF Spores in BaciLuvs. From phato-micrographs made in Havana and in New Orleans. Re- produced by permission of the National Board of Health. Figs. 1 and 2. — Bacillus (ulna ?) found in blood of yellow-fever patient (post-mortem) five days after collection. >< 8,000 diam- eters by Zeiss’s 7 in. objective. Fic. 1. — Rods joined in leptothrix chain. Fig. 2. — A single rod showing spore at one extremity. Fie. 8. — Spores of Bacillus developed in rotten potato, New Orleans, April, 1880. > 1,500 by Zeiss’s 7, in. objective. The large cells are some species of Saccharomycete, which was also pres- ent in the same specimen. Fie. 4. — Development of bacilli from spores, from culture ex- periment with fish gelatine solution. X 1,500 diameters by Zeiss’s py in. objective. 128 PHYSIOLOGY OF THE BACTERIA. Cohn, who had in his first publications refused to the bacteria the property of reproduction by: spores, thinking that the facts observed by Hoff- mann related to different beings, has verified the experiments of Koch upon the development of B. anthracis, and has himself demonstrated sim- ilar phenomena in B. subtilis. In culture experiments made with infusion of hay, we see, at a certain moment, in the homo- geneous filaments of the Bacilli very refractive corpuscles making their appearance. Each of them becomes a spore, oblong or in the form of a short filament, highly refractive, and with well-defined outlines. We find the spores ar- ranged in a simple series in the filaments. As soon as the formation of spores has terminated, the filaments can generally no longer be distin- guished, and one would say that the spores were completely free in the mucus; but their linear arrangement shows always that they are produced in the interior of filaments. Little by little these dissolve, being reduced to a fine powder; and the spores fall to the bottom of the liquid, where they are found in abundance. The germination of the spore does not seem to occur in the same medium; but if we take a spore from the deposit formed in an infusion of boiled hay, and transport it into a new infusion, we see the spore swell up, and a short tube form itself at one of its extremities: at this moment it resembles a bacterium with a head. Soon the very refractive body disappears, the tube stretches out into a short rod of Bacillus, com- DEVELOPMENT OF THE BACTERIA. 129 mences to move, and becomes jointed by trans- verse division. Koch, in cultivating the bacteria of charbon in aqueous humor from the eye of the ox, has ob- served some facts exactly similar, both as to pro- duction of spores in linear series in the filaments of Bacillus anthracis and as to the germination of the spore and the birth of a new rod. According to Van Tieghem, the development of Amylobacter is as follows: “The development of a Bacillus includes four successive periods. In the first, the body, cylindrical and slender, recently developed from a spore, stretches out rapidly, and is partitioned; the articles soon separate (B. subtilis), or remain united in long filaments (B. anthracis). This is the stage of growth and multiplication, two things which at bottom are but one. «Secondly, the articles previously formed, having ceased to elongate and divide, increase sensibly in magnitude, becoming the seat of interior chemical transformations ; and this increase in size operates according to circumstances, in three different man- ners, with some intermediate forms. Sometimes it occurs uniformly throughout the length of the article, which remains cylindrical; sometimes it is localized, either at one extremity, which is swollen like a tadpole, or in the middle of the article, which swells to a spindle shape. This is the stage of enlargement, or of nutrition, solitary and si- multaneous, which prepares the following state. “In the third period or phase of reproduction 9 130 PHYSIOLOGY OF THE BACTERIA. there is formed in each article so nourished a spherical or ovoid spore, homogeneous, highly refractive, having a dark outline. At the same time, the protoplasm which occupies the rest of the cavity disappears little by little, and is re- placed by a hyaline liquid, which separates the spore from the membrane; this dissolves in its turn, and finally the spore is set at liberty. If the article is swollen in tadpole shape, it is in the ter- minal swelling that the spore has birth; if it is spindle-shaped, it is near the middle; if it is cylin- drical, it may be at any point whatever, but is usually near one extremity. The spore when set free germinates under favorable circumstances. At a point where its circumference becomes pale, it gives out a little tube slightly more slender than itself, which elongates rapidly and divides. This fourth period of development or germinative phase brings us back to our point of departure.” Sporangia. — Finally, not only do the bacteria develop spores in the interior of their filaments, slightly modified in form, but we may also observe the formation of a veritable sporangium contain- ing many spores. The unpublished observations of M. Touissant, Professor of Physiology in the Veterinary School of Toulouse, give this result, which he has kindly communicated to me. In cultivating spores of the bacteria of charbon in the serum of the blood of the dog, under the microscope, in the warm chamber of Ranvier, Toussaint has seen the filaments take a transverse DEVELOPMENT OF THE BACTERIA. 131 diameter almost double the ordinary diameter, then the protoplasm of the filament to gather together at certain points,—a fact clearly made out, as in the parts where the protoplasm was wanting the bacteria had lost all refractive power. Finally, at a later period the points occupied by the condensed protoplasm augment considerably in volume, and form some ovoid organs more or less elongated, or swollen into a ball, or in the form of a gourd at one extremity. In the interior of these sporangia, from three to six spores afterward form, clearly defined and highly refractive ; then, finally, by breaking up of the membranous enve- lope the spores become free. Toussaint has also followed in the same appar- atus — moist and warm chamber of Ranvier — the mode of germination of the spores. The follow- ing are the most important facts : — The spores are at first highly refractive and animated by brownien movements; at the end of half an hour to an hour, at a temperature of 37 to 40°, in urine, aqueous humor, or serum, the spores lose their refractive power, and their brown- ien movements cease almost entirely; then the spore assumes an aspect slightly granular, it be- comes elongated in the direction of its greatest diameter (they are oval). After two hours of culti- vation, the bacterium has two or three times the dimensions of the primitive spore; the elongation makes rapid progress, and four to six hours from the commencement of the cultivation, some may 132 PHYSIOLOGY OF THE BACTERIA. be found to occupy the entire field of the micro- scope. From this moment the phenomena which occur differ according to the conditions in which the bacteria are placed. Upon the edge of the air-groove in the moist chamber, the bacteria de- velop very rapidly, forming an interlaced mass; and in sixteen to eighteen hours, spores may be seen to appear in their interior, — above all, if the preparation has been exposed to light. Often, in this case, the transverse partitions of the filament cannot be seen. If, on the contrary, the bacterium has not been exposed to light, the spores are a longer time in showing themselves (ten or twelve hours more), and almost always division of the filament precedes their formation. In that case, a spore usually appears at each end of the seg- ment in such a manner that the spores belonging to two successive segments are nearer to each other than those in the same segment. Often, also, a spore aborts in a segment (Toussaint). We have seen above, in speaking of the res- piration of bacteria, that the same observer has noted in the course of his experiments some phe- nomena proving the evident influence of oxygen upon the development of Bacillus. It is the same for the formation of spores. And upon this point Toussaint makes the very just remark that the phenomena occur in a different manner in culture experiments and in the human organism. In char- bon, the bacteria never form spores. They remain always relatively short, even in the points where they form extra-vascular masses, and where conse- DEVELOPMENT OF THE BACTERIA. 133 quently we cannot invoke the movements of the liquid in order to explain their division. The bacteria of charbon, then, take but little oxygen from the tissues: they do not vegetate luxuriantly in the organism; and certainly, if we judge by a calculation necessarily approximative, their devel- opment is seven or eight times less rapid than in the strongly oxygenated serum of culture experi- ments (Toussaint). Polymorphism. — The spores of which we have traced the genesis constitute those germs of which the origin has for a long time been misunder- stood, — those permanent spores or durable spores (Dauersporen), thus called because of their re- markable degree of resistance to temperature, desiccation, and all the agents which kill adult bacteria or arrest their development. These “organs” are disseminated in great num- bers in various media under the form of little rounded corpuscles absolutely similar to the micro- cocct from which it is absolutely impossible to differentiate them. It is, indeed, very probable that the greater part, if not all of these organisms, are the spores of filiform bacteria. In the impos&ibility of recognizing these forms so nearly related, of referring them to such or such a determined organism, the attempt has been made to cultivate them, in order to follow their development. We have just seen the results of this cultivation for the Bacillus ; but, in the hands of the greater number of experimenters, the re- 134 PHYSIOLOGY OF THE BACTERIA. sults of such culture experiments are far from being so certain. Not having succeeded in re- moving them completely from the invasion of for- eign germs, the greater number have seen the most diverse forms develop themselves, and from this have inferred the most remarkable transfor- mations. . Thus, Hallier pretends to have observed the transformation of Micrococcus into various fungi, such as Mucors, Ustilago, etc. The M. of vaccinia comes from Zorula rufescens, which is itself a phase of development of Ustilago carbo; the M. of human variola is derived from a fungus having sporangia and pycnidia, related to Stemphylium sporidesmium ; that of the variola of animals from Cladosporium (Pleospora) herbarum; the M. of the blood of scarlatina belongs to the g. Tilletia; those of glanders and of syphilis from a Coniothecium, etc. In the same way Letz- erich has referred the M. of diphtheria to another Tilletia, the T. diphtherica. The transformation of bacteria into “ Jleviires” (yeast fungi), and these into Penicillium, has been admitted by Hallier, Trécul, and others. But the researches of Brefeld and de Seynes have shown us that this is far from being demonstrated ; in- deed, in his numerous cultivations, de Seynes has never been able to verify such an affiliation; and Nageli in his turn has never been able to obtain a transformation of schizomycetes into budding fungi. It is the same as regards the transformation of DEVELOPMENT OF THE BACTERIA. 135 bacteria into moulds and mildews. In some recent cultivations of moulds, made with care, Nageli has never observed the formation of schizomycetes, and reciprocally. Are we not permitted to be- lieve, now that we know of the formation of sporangia among the bacteria, that the micro- scopists who sustain a polymorphism so extended, have taken these organs, of which they have not been able to follow exactly the development, for the sporangia of Mucorini? This explanation is the more admissible as Trécul has seen the bac- teria “swell up, and transform themselves sepa- rately,” a phenomenon quite identical to that ob- served by Toussaint. En résumé. The only change of form well demonstrated in the present state of science, and the only one which can be compared to natural polymorphism, such as it exists in a great number of fungi, consists in the transformation of spores into Bacteria, Bacteridia, Vibrios, etc., and in the different modes of grouping that the cells of bac- teria take in becoming zooglea, mycoderma, lepto- thriz, ete. To go further would be to lack’ pru- dence and scientific criticism. 136 PHYSIOLOGY OF THE BACTERIA. CHAPTER II. DEVELOPMENT OF THE BACTERIA IN DIFFERENT MEDIA. In studying the conditions of life and of develop- ment of bacteria in the different media, natural and artificial, in which they are met, we will con- sider the actions which they determine (or that they accompany) as particular cases of their nutri- tion and of their reproduction. We will con- stantly take, then, their normal physiology as our point of departure; and we will try to explain in this way the phenomena, so diverse, with which they are associated, — fermentations, putrefactions, con- tagion of infectious maladies, etc. It is especially interesting to study the réle of bacteria in non-nitrogenized chemical media, where they accompany the phenomena called fermenta- tion, properly so called; in nitrogenized media, vegetable or animal, which they transform, as a result of special fermentations, which constitute putrefaction ; in the human organism, where they accompany frequently, if not always, the develop- ment of certain affections having special charac- ters. This will be the object of so many para- graphs. THE BACTERIA IN DIFFERENT MEDIA. 137 § 1.— Rozz or Bacrerta In FERMENTATIONS. We say that a liquid is fermenting whenever modifications occur in its chemical constitution, as a result of the nutrition of organized beings. Two kinds of fermentation are commonly distin- guished. In the first group (false fermentations) are arranged those which are produced by soluble quarternary substances (diastase, soluble ferments) secreted by living cells, from which they may be separated in order to study their action upon fer- mentable liquids. This action is comparable to that of certain mineral acids, which operate in the same manner, either by the breaking up of molecules with addition of water or by the phenomena of hydration. Veritable chemical reagents, when these substances are once precipitated from their solutions, purified and dried, they preserve their properties indefinitely. A sufficient elevation of tem- perature seems to destroy the edifice of their mol- ecule; for they lose all their specific power after having been subjected to a temperature more or less elevated, but always inferior to 100° (212° Fah.). In the second group (true fermentations) are joined all the phenomena of chemical modifica- tion which appear intimately united to the devel- opment of inferior organisms, — alge or fungi (figured ferments). Compressed oxygen by kill- ing these ferments, and chloroform by suspending their vital functions, arrest the progress of these fermentations, while the same agents do not mod- 138 PHYSIOLOGY OF THE BACTERIA. ify at all the action of soluble ferments. Accord- ing to Dumas, borax has, on the contrary, the property of entirely destroying the activity of soluble ferments without absolutely preventing certain true fermentations,—for example, the al- coholic fermentation of glucose. We will see fur- ther on that this property of borax has been utilized in the treatment of catarrh of the blad- der and of certain virulent affections. Although at first view these two groups of phe- nomena seem very different, they may, however, be compared the one with the other. Without speaking of the ammoniacal fermentation of urine, which, as we shall shortly see, may be arranged in either of these groups, we may admit that the only difference between these two series of chemical modifications consists in the fact that in one case the true fermentations being the last term in the interior nutrition of the cell have their seat in the interior of the cell itself; while in the other the first terms of nutrition are always extra-cellu- lar phenomena, having for effect, as Cl. Bernard has shown, to render assimilable or diffusible in the interior of the organism the aliment necessary to the development of every organized being (trans- formation of starch into glucose, of sugar into glucose, emulsion of fats, liquefaction of albumi- noid substances). The study, from a chemical point of view, of these phenomena of nutrition, of these fermenta- tions, since such is their name, has not yet made much progress, and it would be difficult to make a rational classification of them in the present state THE BACTERIA IN DIFFERENT MEDIA. 139 of our knowledge. I will not then seek to clas- sify them, but will content myself with describ- ing them successively, commencing with the best known. I shall only speak of the fermentations caused by the development of bacteria, leaving, consequently, the fermentation which has been best studied, — the alcoholic. I adopt the follow- ing order : — 1. Acetic fermentation of alcohol. 2. Ammoniacal fermentation of urine. 3. Lactic, viscous, and butyric fermentations of sugar. 4. Putrefaction, or nitrification. Acetic fermentation.— The transformation of wine into vinegar is a phenomenon long known and utilized. From a chemical point of view, this transformation is due to oxydation of the alcohol. The following formula represents this reaction : — C-H°O + O? = C?H!0? + H?0. The agent of this oxydation is a micro-organism called Mycoderma aceti. It belongs to the group of the microbacteria, and we have already given the botanical description of it (page 83); but its development presents some interesting peculiar- ities which we think it proper to indicate in the language of M. Duclaux : — “ These little beings reproduce themselves with such rapidity that by placing an imperceptible germ upon the surface of a liquid contained in a vat having a surface of one square metre, we may see it covered, in from twenty-four to forty-eight hours, with a uniform velvety veil. If we suppose 140 . PHYSIOLOGY OF THE BACTERIA. that there are three thousand cells in a square mil- limetre, which is below the truth, this will give for the vat three hundred milliards of cells pro- duced in a very short time.” “The Mycodermi aceti is not always the same. Usually it forms upon the surface of a liquid a soft-looking veil, smooth at first, then wrinkled, which is with difficulty submerged and moistened. If a glass rod is plunged into the liquid, it pierces this veil; and when it is withdrawn, a portion re- mains attached to the rod; and the opening made immediately disappears, being occupied by the veil which seems never to have room enough in which to extend itself. In some unpublished experi- ments I have frequently observed another form of veil, dryer, finer, and sometimes showing prismatic colors. This veil does not wrinkle, but is covered with crossed undulations, having sharp edges, which recall the surface of a honeycomb. Sowed upon the surface of various liquids, it reproduces itself identically, and it is difficult not to consider it a different form of the preceding. Finally, I have also met a species of mycoderma producing well-developed veils, but having scarcely any acet- ifying power, and reproducing itself with this character.” “Tt is difficult to distinguish these forms the one from the other, by the microscope, because of their minuteness. We may, however, say that the second which I have described is sensibly smaller than the first, and the third more attenuated than either of the others. However, the differences are feeble.” This veil is called the mother of vinegar. The THE BACTERIA IN DIFFERENT MEDIA. 141 liquid in which this mycoderma is cultivated should be a little acid, containing one-half per cent of acetic acid, for example. Under these conditions the Mycoderma vini (a species of Saccharomycete), the formation of which should be avoided, finds conditions unfavorable to its existence. Indeed, this second organism, commonly called flowers of wine, has an action quite different from that of the Mycoderma aceti. It consumes the alcohol entirely, transforming it into water and carbonic acid: it also consumes the acetic acid. We must sow the JZ. aceti, if we do not wish to see the M. vini develop in its place, as the germs of the latter seem more widely diffused in the air. In order that the acetification may occur, the oxygen of the air isnecessary. Once submerged, the M. aceti develops, but no longer produces acetic acid. Itis even probable that it consumes the acetic acid already formed, reducing it to the state of water and carbonic acid. It is the same when, developing upon the surface, it has trans- formed all the alcohol. ‘In effect, it is not then arrested in its work; and without changing form or mode of action, it carries the oxygen of the air to the acetic acid which it has produced, transform- ing it into carbonic acid and water. If we add some alcohol to the liquid, the phenomena change: the ‘acid is respected, and the alcohol is transformed anew into acetic acid” (Duclaux). According to the experiments of Mayer, the maximum of aceti- fying power is obtained between 20° and 30° (68° to 86° Fah.), and this power is lost below 10° (50° Fah.) and above 35° (95° Fah.). 142 PHYSIOLOGY OF THE BACTERIA. Ammoniacal Fermentation of Urine. — When urine is freely exposed to the air, we perceive at the end of a short time that it has become strongly ammoniacal. The urea is transformed into carbon- ate of ammonia by the addition of water: — CO(NH2)? + H20 & CO? + 2NH8. Miiller suspected that the deposit of altered urine, of which Jacquemart had already recognized the particular activity, was an organized ferment, but this was only an induction drawn from the analogy with beer yeast. Pasteur showed that this sediment is formed of a mass of spherical globules, united in chaplets, which he considers the agent of ammoniacal fermentation. These glob- ules are Micrococcus ure, Cohn, which we have already described (page 75). This bacterium lives in the interior of the liquid, and not on the surface like the Mycoderma aceti. Acidity is an obstacle to its development; alkalin- ity, on the contrary, favors it within certain limits. Van Tieghem has even seen the fermentation con- tinue until the liquid contained thirteen per cent of carbonate of ammonia. What is the mechanism of this fermentation ? M. Musculus has shown that we may obtain from altered urine a soluble ferment upon adding to it highly-concentrated alcohol: a precipitate is formed, which may be filtered and dried. This precipitate, not at all organized, transforms urea into carbonate of ammonia. A temperature of 80° (176° Fah.) destroys it. This diastase appears, THE BACTERIA IN DIFFERENT MEDIA. 143 then, to be a secretion of the Micrococcus uree ; and perhaps the réle of the bacteria is limited, in the phenomena of fermentation, to the formation of this secretion alone. The ammoniacal transforma- tion of urine would consequently enter into the group of fermentations by the varieties of diastase. According to Arnold Hiller, if carbolic acid be added to urine, it does not become alkaline; on the contrary, the acidity is even augmented, and that notwithstanding a considerable number of bacteria which develop in it. Has the carbolic acid killed the Micrococcus ure, leaving the field free to other organisms capable of living in an acid medium, and of producing other transforma- tions of the constituents of the urine? In the memoir which we here cite, the author, resuscitat- ing the ancient opinion of Liebig, wishes to dem- onstrate that the decomposition of dead organic matters, and putrefaction in general, are phenom- ena purely chemical, — these decompositions being determined by the presence of organic substances, themselves undergoing transformations. We will not stop to consider these views, long since refuted: the experiments upon which they are founded are easily criticised. It is sufficient for me to say that they are in formal opposition with all the observations contained in modern works upon this question. It is especially in relation to ammoniacal fer- mentation that the question of spontaneous gen- eration has been discussed. We have already seen the results arrived at, and will not return to 144 PHYSIOLOGY OF THE BACTERIA. this subject. Let us, however, mention before closing an interesting work by MM. Cazeneuve and Livon, in which are reported some experiments which prove that urine never ferments in a healthy bladder. Lactic, Butyric, and Viscous Fermentations of Sugars. — Saccharine liquids, left to themselves, are susceptible of divers fermentations, which may occur separately or simultaneously. Those which have been best studied are three, — the lactic, the butyric, and the viscous fermentations. We will describe them successively. 1. Lactic Fermentation.— Under the probable influence of a bacterium (ferment lactique of Pas- teur) glucose and the substances susceptible of furnishing it, such as mannite, malic acid, etc., are transformed into lactic acid. From a chemical point of view, there is in this nothing more than a molecular change, lactic acid having the same composition as glucose. Taken in mass, the lactic ferment resembles beer-yeast; its consistence is, however, a little more viscous, and its color more gray. But under the microscope, the aspect is very different, as we have seen in describing Bacterium lineola. An interesting point concerning this fermenta- tion is the action of acids upon the bacteria which produce it (presumably). As soon as the medium becomes acid, even by the lactic acid produced, the transformation is arrested. It resumes its course, if chalk or carbonate of soda is added to the liquid. THE BACTERIA IN DIFFERENT MEDIA. 145 The most suitable temperature seems to be 35° (95° Fah.). We know but little about this fermentation. “Tt merits, however, to be better studied. It is this which causes the spontaneous coagulation of milk: sugar of milk is transformed into lactic acid, which coagulates the caseine. We often see it occur in beef juice or in sour starch water; it must play a part in the formation of sour krout, and intervenes very certainly, and perhaps more than the alcoholic fermentation, in the preparation of bread. Finally, it very ently invades beer, which of our domestic drinks is most exposed, because of its slight acidity, to become the seat of this fer- mentation. All of these facts render it interest- ing, so much the more as it is rarely exempt from complication, and is frequently accompanied, for example, by a commencement of butyric fermenta- tion, far more disagreeable in its products” (Du- claux). 2. Butyric Fermentation. — This is, in fact, al- ways preceded by a lactic transformation, and it is by an ulterior modification that the lactic acid produces the butyric acid. The organism which accompanies it is a bacterium very nearly allied to Bacillus subtilis, Cohn. The reaction represented by the phenomena, from a chemical point of view, is the follow- ing :— 2C®H8O? = CH8O? + 2C0?-+ Hi. —_—_— _—_—__— lactic ac. butyric ac. 146 PHYSIOLOGY OF THE BACTERIA. According to Pasteur the butyric ferment be- longs to his class of anaérobies. This fermentation resembles putrefaction in a great many particulars. Indeed some authors in- clude it under the same head. 3. Viscous Fermentation. — Wines often change so that they contain a mucilaginous substance and mannite. This viscous matter has the same com- position as gum or dextrine (C*H0*); at the same time it disengages carbonic acid. In the fermenting liquid, we find an organism which is not yet sufficiently studied. “There are chaplets of little spherical bodies, of which the di- ameter varies sensibly, according to the kind of wine attacked by this malady (Pasteur). Pasteur has proposed the following formula: — 25(C2H20") + 25H20 = 12(C2H201) + gum. 24(C8H#O8) + 12C02 + 12H20. mannite. which represents the phenomena well enough as it usually occurs. There is produced in the vicinity of 51.09 of mannite and 45.5 of gum for one hun- dred parts of sugar. But sometimes the gum ex- ceeds the mannite in quantity. In this case, according to Pasteur, we can always verify in the liquid the presence of a larger ferment of a differ- ent nature; and the same author adds that, per- haps, in this case the increased production of gum results from the presence of this second ferment, which transforms the sugar only into gum, without THE BACTERIA IN DIFFERENT MEDIA. 147 any correlative formation of mannite. But this ferment has never been isolated. M. Monoyer has explained the variation in the proportion of gum in another manner (see his thesis for the doctorate in medicine, Strasburg, 1862). White wines are more subject than red wines to this fermentation, called grazsse des vins. Accord- ing to M. Francois, the absence of tannin in the white wines is the cause of this disease, and it may be prevented by adding this substance. This remedy is even very highly appreciated in cham- pagne, according to Pasteur. What is the exact action of the tannin upon the gummy ferment? The only means of knowing is by cultivating this ferment in a state of purity and treating it with this agent. We have united together the lactic, butyric, and viscous ferments, because all three manifest them- selves in the same liquids,—wines, beer, sweetened water, etc.; and because they have for effect the transformation of glucose. We ought to say a word here of some other inferior organisms, per- haps bacteria, observed also in the same liquids, but which have not been as well studied. Not only are they not known systematically, but we do not know precisely what is their chemical ac- tion upon the elements of the medium which nourishes them. I shall only enumerate them. 1. Ferment of Turned Beer (Pasteur). — “These are rods or filaments, simple or articulated into chains of variable length, of about 1 » diameter. 148 PHYSIOLOGY OF THE BACTERIA. A high power shows them divided into a series of shorter rods, scarcely born, not yet mobile at the articulations, which are scarcely indicated.” 2. Micrococcus of a beer, having a particular acidity, distinct from that of beer piqué, having an acetic odor. “It consists of grains resembling little spherical points jointed by pairs or in fours square” (Pasteur), etc. § 2.— Rote or THE Bacteria IN PUTREFACTION AND NITRIFICATION. While in the fermentations which we have just passed rapidly in review, we have always been able to study, at least summarily, the chemical action of the different organisms, we are now about to find ourselves in presence of phenomena far more complex. We will have to consider a great number of these vegetables at work, without its being possible to assign to each its réle, or to say what is its function. The agent of the nitric fermentation has not as yet even been seen, and it is only by analogy that we class this nitrification with the true fermentations. It is not only because of the obscurity which still exists in regard to a great number of peculiar- ities of these two phenomena, that we have united them in the same study. From the point of view of the circulation upon the surface of our globe of the elements essential to the constitution of organisms, they play an analogous rdéle, although opposite the one to the other. THE BACTERIA IN DIFFERENT MEDIA. 149 Let us consider, for example, nitrogen in plants. This element, of which the atmosphere is the res- ervoir, does not enter directly into combination, as does oxygen, with the other elements which with it are to constitute the immediate principles of the tissues. The chemical properties of nitrogen may be characterized in two words, — great resistance to entering into combination when it is free, and great facility, on the contrary, in passing from one combination to another when once it has associated itself with other elements. The circulation of nitrogen in a state of com- bination upon the surface of the globe is also an interesting question of general physics, as well as the circulation of carbonic acid, of water, and of the air. Let us seek to sketch the march of this cir- culation. Whence comes the ammonia which is found in the sea, in the clouds which come to us from equa- torial regions, in the dust of the air? The only known source is the fermentation of organic mat- ters out of reach of the oxygen of the air. It is to this sort of fermentation that we owe the for- mation of peat and the immense masses of com- bustible minerals which have formed during nearly all the geological periods. We see this sort of fer- mentation develop itself when we expose an or- ganic liquid to the air, but only in the inferior part of the liquid, the oxygen which is dissolved near the surface being arrested in the superficial zone, where a very different fermentation occurs. 150 PHYSIOLOGY OF THE BACTERIA. The latter is essentially oxidizing ; the material is almost completely burnt, forming water and car- bonie acid; at the inferior part, on the contrary, a reduction is produced so energetic that hydrogen is disengaged. The metallic sulphates are there transformed into sulphites, and even crystals of sulphur are sometimes found (see the history of the Beggiatoa, page 91). We see then the source of the ammonia, which, distributed upon the soil by the winds and the rains, becomes a powerful fertilizer. Now, vegetables do not absorb nitrogen under the form of ammonia, but under the form of nitric acid. Howis this transform- ation of ammonia into nitric acid effected? The observations of Erdmann, Mensel, and T. Phipson show that in the phenomena of destructive putre- faction, nitric acid, far from being produced, is on the contrary reduced to the state of nitrous acid; on the other hand, Th. Schloesing and A. Miintz conclude from their experiments that in the pu- trefactions essentially oxidizing produced by Peni- cillum glaucum, Aspergillus niger, Mucor mucedo, etc., there is no formation of nitric acid. But, according to these authors, nitrification is a spe- cial phenomenon which takes place in every soil sufficiently loose to permit a free circulation of air, and of which the agent is a micro-organism. This organism has not yet been perceived, it is true; and it is evident that it would be difficult to seek and observe, because of its peculiar situation. But the action of chloroform upon nitrification tends to prove that the agent of this process is THE BACTERIA IN DIFFERENT MEDIA. 151 truly an organized ferment. Indeed, chloroform, this anesthetic, suspends nitrification, and seems even to kill the ferment. Leaving, then, this phenomenon, but little known, we may distinguish in the agents of pu- trefaction, or more generally of fermentation, two groups of micro-organisms, — one oxidizing, the other reducing. The first are observed upon the surface of liquids undergoing putrefaction. We may distin- guish a great number of forms,— Bacterium termo, Monas crepusculum, Spirillum, etc. We ought also to include Mycoderma aceti, which, like the others, vegetates on the surface of liquids, and a great number of organisms of which we cannot speak here. The second are met, on the contrary, in the interior of liquids or of fermentable bodies; they are analogous to the butyric and lactic ferments, and perhaps to the other agents of diseases of wine and beer previously enumerated. En résumé, the little beings which we have been considering have an important réle: they cause the return of dead organic matter to the atmos- phere and to water. “Without them, organic matter, even exposed to the air, would not be destroyed or would be transformed with extreme slowness, in consequence of a slow combustion produced by oxygen. With them, on the contrary, its destruction takes a rapid march and becomes complete. If, then, the equilibrium is maintained between living nature 152 PHYSIOLOGY OF THE BACTERIA. and dead nature, if the air has always the same composition, if the waters are always equally fer- tilizing, it is thanks to the infinitely minute agents ' of fermentation and putrefaction” (Duclaux). But the rdle of bacteria is not limited to this. “‘ They invade also the living organism,” says Du- claux, “ and bring in their attack this double char- acter of infinite smallness in the apparent means and powerful destructive energy in the results. From this source come diseases of which medicine, not long since, did not know the cause, and which she only commences to refer to their veritable origin. For those who are au courant with the first steps which she has made in this new line of research, with the fecundity of her first glimpses, with the richness of her first results, it is not doubtful that she will soon succeed in demonstrat- ing the parasitic nature of the gravest epidemic maladies.” § 3.—RdéLte or THE BacTERIA IN Contagious MALADIES AND VIRULENT AFFECTIONS. We shall first pass in review the different af- fections in which the presence of bacteria has been indicated, whether they have been given as the cause of the malady or considered as simple epiphenomena. Septicemia.— According to the hypothesis of Borsieri and of Gaspard upon the nature of septic blood, Sédillot demonstrated by some very con- clusive experiments that the infective power is due to formed elements (des éléments figurés). Plate [X. AMeiselhith PLATE IX. Copied from photographs by Koch in Cohn’s ‘‘ Beitrdge zur Biologie der Pflanzen,’’ Bd. I1., Heft 3. Fie 1.— Zooglea ramigera from fluid containing rotting alge. X 200 by Seibert’s immersion objective No. 7.! Fie. 2. — Spirillum undula. X 500. Fig. 3. — Bacillus (subtilis?), from hay infusion, showing flagella. X 500. Fig. 4. — Spirochete from human mouth, resembling the Spiroch- ete Obermeieri of relapsing fever. X 500. Fie. 5.— Bacilli, with spores from rotten onion. > 500. Fie. 6. — Bacilli, with spores from surface of rotten potato. x 500. 1 A higher power (500) shows that these branches are made up of oval bacteria, 154 PHYSIOLOGY OF THE BACTERIA. The first experiments of Davaine brought him to the following conclusions: “The effects of pu- trefying substances do not go beyond the animal into which these substances are injected. The toxic agent of putrid matters does not regen- erate itself. Putrefaction acts upon the animal economy as a poison.” The first opinion should have for it the authority of Robin. Already in 1864, Leplat and Jaillart, after a series of inoc- ulations made with septic blood, arrived at de- ductions analogous to those of Robin. At the same epoch, Billroth and Weber, having injected the gases of putrefaction, expressed the opinion that the septic agent was of a molecular nature (particulate). Bergmann, of Dorpat, admitted as contagious agent an azotized substance, not organ- ized, resisting alcohol and ether at a tempera- ture of 100°, and passing through filters. This theory was identical with that of Panum. It is to Pasteur that the honor belongs of having first affirmed the parasitic nature of septicemia. This communication was followed by confirmatory ex- periments by Coze and Feltz. These experiment- ers also proved that the bacteria of putrid blood do not possess the property of traversing the epi- thelium, and that “the infectious element gains in passing through similar organisms.” In 1868, Davaine, changing his first opinion, admitted the presence of bacteria in the blood of animals which die of septicemia. Hallier of Jena and Béchamp of Montpelier also believe in the presence of a micro-organism, — Micrococcus for Hallier, Micro- zyma for Béchamp. THE BACTERIA IN CONTAGIOUS MALADIES. 155 Coze and Feltz, in their work, have demon- strated the constant presence of bacteria in the blood of animals dead from septicemia. This cor- relation has driven them to admit that “there is a direct relation between the infectious acci- dents and the little foreign organisms which play, in the blood, the réle of ferments, and reproduce themselves.” New researches confirmatory of the first have been communicated to the Academy by the same authors. Opposed to these conclusions upon the bacterial origin of septicemia, some ex- periments have recently appeared in England, then in Berlin, which weaken them. Zuelzer, struck by the analogy which exists between septicemia and intoxication by atropine (dilatation of pupils, in- testinal paralysis, acceleration of heart’s action), has sought for the presence of an alkaloid by the method of Stas. In collaboration with Sonnen- schein, he has succeeded in discovering it. Bac- teria cultivated artificially, and introduced in considerable quantity into the mouth, under the skin, and into the vessels of various animals, have never seemed to him to produce septic accidents. But the scene changes as soon as an addition is made to the injected matters of two to five centigr. of neutral sulphate of atropia. The period of in- cubation always lasted from nine to twelve days. The same year, Riemschneider deduced from his observations the same result, and confirmed thus the similarity between atropine and sepsine. The bacterial origin of septicemia received, however, a new support from the experiments of Vulpian. 156 PHYSIOLOGY OF THE BACTERIA. Having injected into a rabbit two drops of blood from a man who died of pulmonary gangrene, the animal died at the end of twenty hours. Nu- merous bacteria were found in its vessels. The liquid extract of these, injected into other rabbits produced death in twenty-four hours, and the same parasites were observed in their blood. According to Henrot the bacteria penetrate by the pulmonary mucus membrane, and only ‘act in contact with blood rendered “ phlogogéne ” by pus. There is then a necessity for two producing causes. In support of his opinion the author cites the following experiment. He injects into the jugular of two rabbits a mixture of distilled water and pus, for the purpose of rendering the blood “ phlogogéne;” in two others he injects pulverized coral suspended in water. One of the first rabbits and one of the second, placed in a pure air, resist perfectly. The two others are subjected to ema- nations from putrefying “anatomical” fragments. The rabbit into which pus had been injected died in three days, the second was still living at the end of a month. Cavafy admits the presence of bacteria in septic liquids, but does not regard them as the efficient cause of the thromboses following in- oculations. According to Moritz Traube and Gschleiden, living organisms into which one in- jects blood containing a great quantity of the bacteria of putrefaction, do not suffer any dur- able harm from the injections.' At the end of 1 I have injected various liquids containing bacteria into the circula- tion of dogs and into the cellular tissue of rabbits, but have never seen any serious results follow such injections. —G. M. 8. THE BACTERIA IN CONTAGIOUS MALADIES. 157 twenty-four hours, the arterial blood drawn from a rabbit into which one and one half. centimeters of liquid containing bacteria had been injected, can be preserved (by protecting it from exterior germs) during several months, without presenting traces of putrefaction. The bacteria then are dead in the living organism. Nevertheless, the living blood is powerless to resist beyond a cer- tain point. These results seem difficult to rec- oncile with those which Feltz has reached as the result of new researches with the toxic principle of putrid blood. Compressed air passed through a septic liquid has no influence upon its toxic prop- ertiés or upon the minute beings contained in it: there is simply a diminished movement of the vibrios. In a vacuum the toxic power is diminished: the Cocco-bacteria and bacteria be- come motionless, the vibrios and spiral bacteria lose their activity, but the smallest forms are not killed. W. Moxon and J. F. Goodhart have recognized the presence of bacteria in the blood and in the inflamed tissues of septicemic pa- tients. According to Virchow, also, the active agent is a bacterium which, injected, with or without putrid liquid, produces death by septic intoxication. Livon and Zuelzer have never observed any symptom of putrid infection to follow injections of these micro-organisms into the blood. In presence of so many divergent opinions, each supported by scientific authorities, we do not feel justified in adopting any definite conclusion. 158 PHYSIOLOGY OF THE BACTERIA. The experiments of Coze and Feltz, however, as well as those which confirm them, lead us to consider the constant presence of bacteria in pu- trid blood as a great probability in favor of the parasitic genesis of septicemia. There is a variety of septicemia which presents the closest resemblance to that of which we have just spoken; namely, puerperal septicemia. The preceding researches, with their consequences, are all applicable to this form of septicemia, and ex- plain to us its nature. This manner of seeing seems to us justified by the labors of Orth of Bonn, according to which the lymph and the blood contain Micrococci in considerable numbers. Klebs has verified the presence of the same parasites in the putrid infection consecutive to gun-shot wounds. Like the preceding authors, Birsch-Hirschfeld recognizes in the liquids of septicemia the presence of Micrococci, and does not admit any other parasites. Charbon. — A malady in which the influence of inferior organisms has been especially sought is charbon. We will examine successively the results fur- nished by experimental pathology and by clinical observation, and will finish by a general discussion of the nature of charbon. Although this affection has been known and studied from the highest antiquity, and was de- scribed by Chabert (1782), Gilbert (1795), and many others, its parasitic nature has not long been THE BACTERIA IN CONTAGIOUS MALADIES. 159 known. Let us note, however, that Fuchs, Brau- ell, Pollender, and Delafond, had remarked some corpuscles in the blood of animals attacked with charbon. Prof. Delafond made, twenty years ago, some researches, which he communicated to the Central Society of Veterinary Medicine, upon the rods of sang du rate. Davaine, who had observed, with Roger, the presence of rods in the blood of charbon as early as 1850, did not attach any im- portance to the fact. After the work of Pasteur in 1861, he resumed his researches and the results which he obtained were communicated to the Acad- emy of Sciences the 27th of July and the 10th of August, 1863, then the 22d of August, 1864. His experiments established the fact that the blood of animals attacked with charbon contains organisms (éléments figurés), and that, injected into a healthy animal, it kills it by reproducing the same symp- toms. There remained a step to make, to prove that the bacteria alone possessed the infective power, even in epidemic cases. Notwithstand- ing the labors of Signol (1864) corroborating his discoveries, Davaine did not fail to find oppo- nents. Leplat and Jaillard made known the re- sults of their experiments, according to which the bacteria were not the cause of sang de rate. In 1867, Bouley and Sanson, and in 1870, Bail- let, studied the nature of the malady known under the name of mal de montagne. Klebs, in Switzerland, having, with Tiegel of the Pathological Institute of Berne, made some negative injections with filtered blood (of char- 160 PHYSIOLOGY OF THE BACTERIA. bon) demonstrated thus that the disease was truly due to the solid particles; but he could not, as he did, affirm that the bacteria alone were endowed with virulent power, for he included at the same time all the other solid elements (fibrine, globules), and could not therefore eliminate the granulations of a virus other than the bacteria. Klebs does not believe that the bacteria cause death by asphyxia. This view is also sustained by Recklinghausen and Waldeyer, who believe that death results from embolism: according to Burdon-Sanderson, on the contrary, this is not the case. The observations and experiments up to this time demonstrated that the blood of charbon would transmit the disease. Davaine had said that the bacteria constituted the condition sine qua non of the development of these diseases, but he had against him the experiments of Leplat and Jail- lard. Besides, as he injected at the same time other corpuscles figurées, it was difficult to prove that they went for nothing in the production of charbon. Finally, this theory could not explain certain endemics (pastures in Auvergne). One could truly say, with Burden-Sanderson, that the virulent element can exist in two forms, — one fugitive (bacteria), one permanent, unknown. The point was to demonstrate it. This is what Koch has done. Having taken some bacteria, he culti- vated them in urine, or the aqueous humor of the eye of a horse, and remarked that they under- went a certain elongation, then presented brilliant points of condensation which became free; injected THE BACTERIA IN CONTAGIOUS MALADIES. 161 into the blood of sheep and of rabbits, these cor- puscles produced death with the symptoms of charbon, and the blood of the animals presented numerous bacteria. The appearance of spores in the liquid under cultivation, containing bacteria, occurs in twenty-four hours at 35° (95° Fah.), in three days at 18°; above 45° and below 12° it is no longer possible. Once produced these spores resist putrefaction, desiccation, and alternation of humidity and dryness, during several years. On the contrary, the adult form of the Bacillus an- thracis dies under the influence of putrefaction and of oscillations of temperature. It has not seemed to develop itself in the dog, the cat, birds, and cold-blooded animals. The immunity which these enjoy has recently been the object of a study by Pasteur, Joubert, and Chamberlain. Believing that it might be attributed to their temperature, incompatible with the life of the bacteria, they have refrigerated a fowl, and have ascertained that it lost this immunity. Besides, by placing the infected animal in an oven at 30° (86° Fah.) they have seen the temperature come back rapidly to the normal and the symptoms of charbon to re- cede. The labors, then, of Koch add an additional element of probability in favor of the parasitic theory. They show us the existence of an organ- ism which we would be able to invoke as the cause of spontaneous epizootics. All these results Cohn of Breslau has obtained upon repeating the experiments of his compatriot. ul 162 PHYSIOLOGY OF THE BACTERIA. In France, Toussaint commenced, March 21, 1875, a series of successful inoculations upon rab- bits, with blood obtained from the spleen and an abdominal tumor of a sheep which had died of the mal du rate. These specimens had been sent to Chauveau by Joly, veterinary surgeon at Gien. Having preserved some blood in the air, Tous- saint remarked, as Davaine had done and as Koch had observed, that putrefaction kills the Bacillus ; enclosed in a close vessel, it succumbs as soon as oxygen is wanting, which occurs sooner when the temperature is elevated. It was upon the presentation of these results to the Academy of Sciences that Cohn expressed the opinion that charbon is not due to a bacterium, but to a special virus. If the filtered blood does not act, it is because the filter, at the same time, retains the-virus. Pasteur, in his letter of Aug. 18, 1877, replies that a virus would be impotent to resist the numer- ous cultivations endured by the liquids in his ex- periments, and that the bacteria alone remaining, it was very logical to attribute to them the infec- tious power possessed by the liquid of the last cultivation. Paul Bert had at first believed, with Cohn, in the existence of a virulent agent other than the bacteria. Indeed, after having treated blood of charbon with compressed air and alcohol, which kill bacteria, he had been able to transmit charbon. But, abandoning this first idea, he expressed him- self as of the same opinion as Pasteur and Joubert THE BACTERIA IN CONTAGIOUS MALADIES. 163 (July 30 of the same year), recognizing that the persistence of the virulence is due to spores (cor- puscles germes) which resist all the causes of de- struction. Quite recently, finally, Toussaint, while studying the mechanism by which the bacteria cause the death of rabbits, horses, and sheep, arrives at the conclusion that it is because of asphyxia of me- chanical origin, — embolism of the pulmonary ca- pillaries. The phlogogéne action of the vibrionien is some- times such that, in addition to embolism, there is a rupture of the capillaries, and even lesions graver still. “The phlogogéne material is more active, accord- ing to the subjects from which the bacteria are obtained. The animals which I have studied may be arranged as follows: the rabbit, guinea-pig, sheep, ass, horse, dog.” As to the hog, it is not at all susceptible. In the last place, Toussaint has presented, through Bouley, a note upon a form of charbon caused by a Vibrion aérobie. This affection was already recognized as contagious, but the agent of conta- _, gion was not known. Toussaint has found that it is caused by a Bacterium, differing in certain char- acters from Bacillus ; he has cultivated this mi- crobe, and has seen it reproduce itself under the microscope, in an apparatus invented by Ranvier. The malady has been transmitted to rabbits in the same burrow without inoculation. By taking the excrement, reduced to powder, of 164 PHYSIOLOGY OF THE BACTERIA. an infected animal, and sowing it upon the food given to an animal in good health, the latter has contracted the disease. Malignant Pustule without Bacteria. — Besides the numerous facts concerning charbon, in which the presence of a bacterium has been verified, it is proper to cite those cases in which none has been discovered. Some authorities, such as Tous- saint, Mannoury, and Salmon, who have given these instances, consider this absence of bacteria a favorable prognostic sign. The following well- marked example has recently been observed : — Louis Donin, a tanner, aged forty, was admitted to the Hotel-Dieu of Lyons, June 15th, 1876, service of Fochier. On the morning of June 13, he had noticed three large flies, eagerly attacking the skins upon which he was working. One of them bit him in the face. The same day his cheek swelled ; during the night a large vesicle formed, surrounded by an areola of other smaller vesicles; the skin having become pruriginous, Donin rubbed the central vesicle. Upon his arrival bis general condition was satisfactory. Upon his left cheek was seen an areola of little vesicles surrounding a slough having a diameter of less than a centi- meter. The periphery was oedematous and hard, trembling and extended downwards as far as the xiphoid appendix. The eyelids and the oedema- tous lips were opened with difficulty. In order to verify the diagnosis, Toussaint inoculated a rabbit with the débris of a pustule; a second, with blood; THE BACTERIA IN CONTAGIOUS MALADIES. 165 and a third, with serum. The result of these three inoculations was completely negative. The micro- scopic examination by Charpy and Colrat did not reveal the presence of any vibrionien. On the 16th of July, the patient left the hospital cured. Let us add that the interne of the service, having punctured his finger with a syringe employed in making injections of carbolic acid (twenty per cent), did not experience any ill effects. Darreau, veterinarian at Courtalain, attributes to bad food this variety of charbon, in animals, without the presence of bacteria. He has de- scribed an epidemic on a farm where the forage was of bad quality. Charbon is then due, ac- cording to him, to impoverishment of the blood. Decroix, veterinarian in the army, has examined with the microscope the blood of horses submitted to his observation, from the jugular vein, and also the tumors. He has never found any bacteria. The horses have recovered. These experimental and clinical results have permitted Bouley to estab- lish the unity of the charbonneuse malady, contrary to the opinion of Prof. Bouillaud, who renews the hypothesis of a multiplicity of charbonneuse affections. In effect we see the same bacterium everywhere producing the same disorders. In the very rare and generally favorable cases of charbon which do not seem to be of bacterial origin, we may say with Pasteur, “ When the parasite has not been perceived, it is probably because sufficiently high powers have not been used. The phlogogéne ac- 166 PHYSIOLOGY OF THE BACTERIA. tion of the bacteria, brought to light by Toussaint, is necessary in order to explain the production of the tumors of charbon.”’ Davaine, in consideration of the immobility of the Bacillus anthracis, admits that every tumor results from a local inoculation. We have called attention to the fact that the virulent agents of variola and of rugeola, although motionless, pro- duce nevertheless local manifestations. In the second place, the charbon of the horse is often accompanied by internal tumors of which the or- igin evidently cannot be an external cause. Fi- nally we have pointed out by Bouley some horses of La Plata in which the local manifestations did not appear until after the general symp- toms. This view had already been sustained by Chabert. However, notwithstanding all the proofs furnished turn about by experimental pathology and clinical study, one desideratum still remains. It is necessary to verify the presence of the spores of Bacillus anthracis in the lands where charbon prevails as an epizootic and to discover its means of transportation. Before abandoning this question, we think it proper to examine the efficacy of antiseptic treat- ment. Carbolic acid, studied by Koch, has been employed with success; boracic acid, which acts upon the bacteria by depriving them of oxygen, has been utilized by Decroix, veterinarian of the army; tincture of iodine, employed, like carbolic acid, — by subcutaneous injections,— has given rise to grave accidents. Beside these general THE BACTERIA IN CONTAGIOUS MALADIES. 167 proceedings based upon the idea of an infection of the entire organism, are placed the local treatment destined to destroy the bacteria at their point of entry: thesé are, caustic potash, sublimate, the paste of Canqouin, the hot iron. These two cate- gories of means employed sometimes alone, some- times simultaneously, show that the idea of the clinicians has always been the destruction of an infectious organism. Variola.— The partisans of the parasitic na- ture of variola may be divided into two groups: 1. Those who, with Coze and Feltz, attribute the virulence to a Bacterium; 2. Those who, with Luginbiihl and Weigert, attribute it to a Micrococcus. Coze and Feltz have indeed dis- covered Bacteria in the blood of variola, and this blood injected into the veins of a rabbit has given it a mortal malady, which these observers consider variola. But Chauveau has shown that the af- fection which proved fatal to the subjects of the experiment was not and could not be variola. Another objection is that Bacteria are not found in all those who suffer from variola. However, Coze and Feltz and Baudouin affirm that there are in variolous blood numerous rods, of which the appearance is similar to that of Bacterium bacillus and Bacterium termo of Miiller. These elements do not at all resemble those found in other infec- tions, and when inoculated possess the power of reproducing variola. As to the Micrococcus of variola, they have PLATE X. Copied from photographs by Koch in Cohn’s ‘‘ Beitrige zur Biologie der Pflanzen,” Bd. IT., Heft 3. Fra. 1. — Bacilli of Miltzbrand from the substance of the spleen. x 700. Fig. 2. — Bacilli of Miltzbrand in blood of basilar artery col- lected two days after death. X 700. Fig. 3. — Spirillum Obermeiert. X 700. Fic. 4.— Bacilli of Miltzbrand cultivated in aqueous humor, showing development of spores. x 700.! 1 The lithographer has not succeeded in making a satisfactory copy of Koch’s photo-micrograph, in this figure. AMetsellith THE BACTERIA IN CONTAGIOUS MALADIES. 169 been studied by Luginbiihl, Weigert, Hallier, and Cohn. ‘These micro-organisms possess the characters of all the spherical bacteria, and are found in the variolous pustules, the rete Malphigu, the liver, the spleen, the kidneys, and the lym- phatic ganglia. We can only insist upon the fact of the concomitance of the variola and the pres- ence of Micrococcus, since experiment cannot be resorted to in this disease, of which the complete evolution only occurs in man. We also find in vaccine lymph analogous Micrococei, in every point of view, to those of variola. Cohn considers them both, not as distinct species, but as two races of the same species, — the Micrococcus vaccine. Scarlatina.—Coze and Feltz have found in the blood of scarlet-fever, taken from patients, living or recently dead, some rods as well as mo- bile points. This blood injected into the cellular tissue of rabbits has sometimes produced death, and the blood of the animals experimented upon has presented the same bacteria as human blood of scarlatina: they are simply a little larger and longer. As to the mobile points, they appear to correspond to the Micrococcus of scarlatina described by Hallier. Rugeola.—The examination of the blood of mea- sles has shown to the same experimenters, bac- teria of extreme minuteness and great mobility. The inoculation of this blood has not produced the death of rabbits; however, these animals have 170 PHYSIOLOGY OF THE BACTERIA. been sick for two or three days and have pre- sented in their blood very slender and active rods. In the period of invasion the nasal mucus already contains small bacteriform elements. Diphtheria. — All the labors undertaken since Tigri, by Trendelenburg, CErtel, Letzerich, Tom- masi, and Hueter, from a parasitic point of view, have attributed diphtheria to the presence of a Micrococcus. There is however a single exception, Eberth of Zurich, in a work published in 1872, regards a Bacterium as the agent of the diph- theritic contagion. According to new researches, which appeared in 1873, the pus of pyzmia, or of purulent perito- nitis, inoculated, produces diphtheria because of the presence in it of bacteria. Laboulbéne had already pointed out the presence of Bacterium, accompanied by Vibrios and Mi- crococcus in pseudo-membranous affections. Some researches made in collaboration with Robin had given the same result, but these savanits did not admit a relation of cause to effect between the micro-organisms observed and diphtheria. Ac- cording to Duchamp, as shown by experiments cited in his inaugural thesis (1875), there are in false membranes Bacteria, Vibrios, and granu- lations. Taken alone, these micro-organisms appear to possess a very injurious action, but their inocula- tion does not produce diphtheria. The demonstra- tion of a causal relation between the Micrococcus THE BACTERIA IN CONTAGIOUS MALADIES. 17] and diphtheria is not, then, yet established by these last experiments. Typhoid Fever.—Tigri first found bacteria in the blood of a man dead with typhoid fever. These organisms were also found by Signol (1863) and Mégnin (1866) in the blood of horses at- tacked by a disease called by the veterinarians typhoid fever. This blood, by inoculation, pro- duced the death of some rabbits, with the same alterations in the blood. Coze and Feltz (1866), having inoculated some rabbits with the blood of typhoid fever, have produced results which they consider analogous and as accompanied by the same pathological lo- calizations in the glands of Peyer. The blood of an injected rabbit may be used upon a second rabbit, with positive results, as in variola and scar- latina. The species of Bacterium which is found in this case recalls the Bacterium catenula, but its dimen- sions are less. Glanders and Farcy.— The universal recogni- tion of the contagious power of a liquid coming from an animal with glanders had, a priori, led to the supposition of an element of special con- tagion. The first indication was given by Chris- tot and Kiener (1868). These experimenters discovered in the secretions and vascular glands of animals attacked with glanders, bacteria of two sorts: 1. Rods, sometimes having a vibratory mo- tion without changing place, sometimes having 172 PHYSIOLOGY OF THE BACTERIA. a rectilinear or eccentric motion of translation ; 2. Some spherical granules of variable diameter, homogeneous, animated by a rapid gyratory move- ment and a movement of translation in various directions. The latter are certainly Mitcrococct. Chauveau, in an experiment designed to demon- strate that the organisms alone are active, took ten grammes of pus from a pulmonary abscess of a horse attacked with acute glanders: the virulent elements were so numerous that the water became opalescent. This pus was washed four or five times in five hundred grammes of distilled water, was then collected and dried, and finally was inoc- ulated, and the inoculated animal perished with glanders. Another, on the contrary, into which the filtered liquid was injected presented nothing abnormal. The particulate elements are, then, alone active. But in glanders, as in charbon, con- tagion is not always demonstrated. There are cases in which spontaneous origin appears incon- testable (case of M. Boulay d’Avesnes, three cases cited in the “ Recueil de Médecine Vétérinaire,” June 15, 1877). Finally, this opinion has recently been supported by Delamotte, who accords in this with Tabourin, Bonnaud, and Chénier. We might perhaps see in these cases the action of a minute germ, play- ing, in regard to the bacterium of glanders, the same role as the germ of charbon does with re- gard to the Bacillus anthracis. This is an hy- pothesis which no researches have yet confirmed. As proof of the functional analogy which may THE BACTERIA IN CONTAGIOUS MALADIES. 173 exist between the bacteria of! glanders and of charbon, we recall the fact that Bédoin, having mixed some powdered borax (two grammes) with the blood of a glandered horse, has found the bacteria completely motionless at the end of two hours. These results correspond with those which Decroix, veterinarian of the army, has obtained by treating horses attacked with charbon with boracic acid. Ulcerative Endocarditis. —In this affection, it is well settled to-day that the cardiac walls and, above all, the valves are covered with parasitic masses. Some think that the malady is due to the introduction of these parasites into the interior of the tissues; others, on the contrary, like Hiller, deny that the bacteria bear any causal relation with the lesions of ulcerative endocarditis. Ger- ber and Birsch-Hirschfeld have recently made an observation which is a complete refutation of the ideas supported by Hiller. They have found at the autopsy some hemorrhagic foci disseminated in various organs, the greater number of which contained some particular corpuscles belonging to the class of the bacteria. Relapsing Fever.—In 1868, Otto Obermeier discovered in the blood of the sick attacked with recurrent fever certain bacteria, called by Cohn Spirochete Obermeiert. These organisms are only found during the febrile paroxysm; after the ac- cess of fever they disappear, but often they are 174 PHYSIOLOGY OF THE BACTERIA. again found a few hours before the new access. They are no longer found when convalescence is established. Heidenreich, Weigert, Birsch-Hirsch- feld, and Cohn have confirmed these observations. Intermittent Fever.—In all the analyses of air made in the vicinity of lands where this fever prevails, numerous inferior organisms have been found. I refer to a previous work for additional information,’ and limit myself to pointing out the observations of Griffini, who has found in the dew of places subject to this fever, Vibrio bacil- lus, V. lineola, Bacterium termo, B. catenula, etc.? 1 Ant. Magnin, Rech. Geol., Bot. et Stat. sur ’Impaludisme dans les Dombes, et le Miasme Paludéen. Paris, 1876. 2 “ Professors Klebs and Tommassi-Crudelli, who have recently spent some time in the neighborhood of Rome with the intention of investigat- ing the cause of malarial fevers, have published an account of their researches. From an abstract of their report, published in a recent number of the ‘Medical Times and Gazette,’ we learn that the inves- tigators followed a very deliberate plan in the performance of their task... . “ Professors Klebs and Tommassi-Crudelli first succeeded in producing the symptoms of malarial poisoning in animals by injection of watery extracts from the marshy soil. They then proceeded, by the process called ‘fractional cultivation,’ to isolate the active material, that is, the true generator of the disease, supposed to be a living organism. Lastly, they isolated the organisms by filtration; and, comparing the results ob- tained in injections of the filtrate with those produced by the residue containing the organisms, they proved that the poison of malaria resides in these. The fungi obtained appeared as small rods of 0.002 to 0.007 mil- limeter in length, growing into long, twisted threads. The fungus is markedly aerobiotic. If air is excluded, it dies out. The injection of these fungi —true bacilli malarie —into healthy animals always gives rise to symptoms of intermittent fever, with enlargement of the spleen, etc. Later, Dr. Marchiafava, at Rome, was able to demonstrate spores and bacilli in the spleen, the marrow, and the blood of three persons who had died of pernicious fever, showing the same characters as those ob- served by Klebs and Crudelli. In summarizing the results of their in- vestigations, the authors consider the following facts as proved: 1. That THE BACTERIA IN SURGICAL LESIONS. 175 § 4.— Or THE ROLE or THE BAcTERIA IN SureicaL Lestons. Existence of Bacteria in the Liquids Secreted by Surgical Lesions. — Since the day when thera- peutics has entered upon a road truly scientific, the study of the liquids secreted upon the surface of divided tissues has occupied an important place in the observations and researches of surgeons. Little by little the discussion of operative methods has fallen to the second place, so that to-day, both in the press and in the societies, but little attention is given to the mode of proceeding or to the form of the flaps; but the greatest interest is taken in all questions touching the pathological physiology of solutions of continuity. Thirty years ago it was to chemistry that we looked for an explana- tion of the complex phenomena which favor or prevent the cicatrization of wounds: to-day it is above all to the microscope; or rather it is to that part of chemistry which is the most particularly indebted to the microscope for the progress which it has accomplished, that is to say, to the science of ferments, to zymotic chemistry. To show by what labors this tendency has been brought about, to what facts they have led, and what progress has been realized, is the object which we propose to ourselves in this paragraph. it is possible to reproduce malarial infection in every form in rabbits in which it is known in men; 2. That the malaria produced artificially in animals is generated by organisms existing in the malarial soil at a time when the outbreak of the fever has not yet taken place.” — Hxtract from Leading Article in “ Philadelphia Medical Times,” March 18, 1880. 176 PHYSIOLOGY OF THE BACTERIA. Bacteria in Liquids Exposed to the Air.—In order to comprehend the importance of bacteria from a surgical point of view, it is sufficient to put a drop of pus from an open wound under the micro- scope. In the majority of cases the presence of bacteria will be demonstrated. And, truly, there is nothing in this which should astonish us, if we remember what has been said above, since we know the facility with which these vegetables de- velop in all the liquids of the organism, and the resistance which they offer to all but the most powerful agents. However, all pus is not equally suitable for the development of these organisms. It is easy to remark that they are more abundant in pus of a bad character, in that which smells bad and exhales an odor of butyric acid. They are also more commonly found in pus which has re- mained a long time in wounds having hidden si- nuses. But while recognizing these differences, we must confess that there is nothing absolutely fixed about them, and above all that they do not bear a constant relation with the conditions which govern the genesis of putridity. It is certain, also, that the conditions surround- ing the sick person, the quality of the air in which his wound is bathed, are conditions which it is necessary to consider. And this results from what we have said relative to atmospheric germs. For example, when we submit to maceration in distilled water, dust gathered in a hospital, on one hand, and on the other, dust from a different lo- cality, taken in the country, for instance. The THE BACTERIA IN SURGICAL LESIONS. 177 first will much sooner develop Micrococcus, ete., and in far greater numbers (L. Julien). Now it is evident that this result is exactly applicable to the subject which occupies us, since the pus of wounds exposed to the air can be compared, in a certain measure, to the infusions of dust. As to the elements found in pus, they are equally variable. Most frequently the cocco-bac- teria present themselves in the form of little chains (strepto-bacteria). They rarely exhibit any move- ment. The appearance of bacteria upon the sur- face of wounds occurs at the end of sixteen to twenty-four hours. During the first hours follow- ing the division of the tissues, as is well known, the only exudation which appears is a yellowish- pink serum, In this inflammatory exudation, which always contains a considerable quantity of blood globules, the parasites do not at once appear. But, as I have said, at the end of a day or two Micrococct and Bacteria in chains, very small, and of average size, make their appearance. It seems, then, as has been remarked by G. Nepveu, to whom we owe an excellent work on “The Role of Inferior Organisms in Surgical Lesions,” that this first se- cretion of wounds is quite propitious for the de- velopment of bacteria; and, perhaps, we might be able to draw from this fact an argument in favor of their formation and their existence in the blood. Later, with free suppuration, the inferior organ- isms increase still more. It is, however, to be remarked that they are never very abundant upon the surface of healthy wounds. If we gather this 12 178 PHYSIOLOGY OF THE BACTERIA. pus, and preserve it in the open air for some time, we may follow the increasing development of these germs. An important remark, due to Dr. Molliére of Lyons, is that the phenomena of putrefaction are hastened by the presence of blood in the puru- lent liquid. A quantity of pus drawn by aspira- tion from a deep abscess, and not mixed with blood, was exposed to the air for fifteen days, without any bad odor being developed. Bacteria in ‘Purulent Collections not Exposed to the Air.— In 1875, Dr. Albert Bergeron com- municated to the Academy of Sciences (Séance of Feb. 26) the results of numerous observations made in the service of Prof. Gosselin, for the purpose of ascertaining if the pus of abscesses contains bacteria. The following are the conclu- sions of his memoir: — 1. Vibrios are found in the pus of abscesses, without any contact with the external air and without, usually, any indication that the organism is seriously infected by their presence; 2. We can- not admit that in these cases the vibrios have pen- etrated into the interior of the abscess through the lymphatic system, or through the circulatory sys- tem, both being intact. The pus of warm abscesses in adults often contains vibrios; if they occur in the case of infants the fact has not been observed ; 3. The pus of cold abscesses in the adult, as in the infant, never contains them; 4. The vibrios may be considered as indicating a serious inflammatory state, and a certain tendency to decomposition of THE BACTERIA IN SURGICAL LESIONS. 179 the humors which contain them, without, however, as a rule, exercising any toxic action upon the organism; 5. The author is far from rejecting the possible intervention of vibrios in the pathology of purulent infection; and he explains the happy exemption of infants from septicemia, in a majority of cases, by the fact that these organisms are not found in the pus of abscesses in young children. The conclusions of the memoir of M. Bergeron were the objéct of earnest discussions. According to the accepted theory, there ought never to be a development of organisms, unless the germs had been introduced from the air; if, then, we admit the correctness of these observations, the explana- tion given by Pasteur breaks down. Let us add, that many times, by the bedside of the patient, the microscope has furnished results absolutely contradictory. Sometime before M. Bouloumié had formally established, as the result of long con- tinued researches, that pus coming from any col- lection whatever, not in communication, directly or indirectly, with an open wound, never contained organized elements, mobile or motionless, which can be considered as microzoa, or microphytes, except some highly-refractive moving points, often joined together in pairs. We dare not say that the long discussions to which these communications have given rise have thrown any light upon the grave problems which they have attempted to resolve. Let it suffice for us to have pointed out these different points of view. 180 PHYSIOLOGY OF THE BACTERIA. Of the Effects of Bacteria. —It would be rash to attempt to-day to give a definite verdict upon the greater or less noxiousness of the bacteria. At the outset of the studies which disclosed their presence in many pathological liquids, it was be- lieved that we had finally found the true explana- tion of the obscure phenomena which retard or complicate the normal repair of wounds. But what shall we think to-day of the redoubtable réle - which was at first attributed to a microbe, when we ascertain that its development is not fettered by the clinical means which are most highly praised? These are the difficulties of the prob- lem upon which the future will, without doubt, shed some light, but of which —I repeat it — not- withstanding the amount of labor which they call forth every day, it is not possible for us to form- ulate the solution to-day. Let us try, however, to indicate that which experiment has taught us up to the present time. Upon the surface of a granulating wound, not offering to absorption any vascular or lymphatic orifice, it is to be believed that the microbe con- stitutes only a very contingent danger. It may multiply in greater or less degree, and will absorb more or less oxygen, giving birth, perhaps, as a result of chemical decompositions, to a virus upon the surface of the wound, which, notwithstanding, will arrive at cicatrization. But, if a solution of continuity happens to break through the thick layer of fleshy granulations, either by the spon- taneous movements of the patient or by those THE BACTERIA IN SURGICAL LESIONS. 181 which occur in dressing the wound (the pressure and manipulations which it was formerly custom- ary to resort to), a rent being produced, the infec- tious agent will be able to penetrate into the blood current or into the lymphatics, and the door will thus be opened to local or general compli- cations. As a local complication, we should cite, above all, ?abcés de voisinage. If the presence of bac- teria in the pus of spontaneous abscesses is still under discussion, all observers are agreed as to their presence in secondary purulent collections. Bouloumié has taught us that in pus coming from abscesses developed in the parts in the vicinity of a wound, whatever may be its extent and depth, we may verify the presence of all the micro- organisms found in the pus of the wound, or cer- tain ones only, according as the abscess is developed in parts continuous with or contiguous to the tis- sues of the wound. There is then no doubt that, in this case, these elements are absorbed, or at least find their way through the veins or lymphatics. The inflammatory action of micro-organisms, thrown thus into the midst of healthy tissues, even of those which become inflamed with the most difficulty, is easy to demonstrate. The following unpublished experiments upon this pomt have been communicated to us by our friend Dr. Louis Jullien: — EXPERIMENT 1.— Having gathered some dust in the surgical wards at Lyons, I put it in a flask of distilled water. At the end of some days I had thus given rise 182 PHYSIOLOGY OF THE BACTERIA. to the development of numerous micro-organisms, the most common form being Bacterium. The 20th of May, 1878, with a Pravaz syringe, I injected four drops of this liquid into the right ocular globe of a rabbit. Immediately afterward, the iris bulged forward, became clouded, and the pupil dilated irregularly. As a result of this injection a terrible in- flammation was developed. On the 25th I note an intense conjunctivitis and a roughness of the cornea, from which the epithelium has disappeared at certain points. Upon the posterior surface of the cornea is a white cloud occupying the inferior part of the pupil- lary opening, more opaque in certain points and present- ing the appearance of a hypopyon; the iris was still bulged forward, tomentous, of a violet red color; pupil contracted. June 4, the iris is still bulged forward, so as nearly to touch the cornea; the crystalline lens is also pushed forward. June 5. By aspiration I withdrew from the vitreous a sort of membrane having the form of a whitish fila- ment. Upon examining this with the microscope, I recognized the presence of pus globules, cryptococcus, and bacteria. June 10. The ocular inflammation has disappeared, but a cataract remains. Exp. IJ.— The same as the preceding. When the syringe was withdrawn from the vitreous, into which four drops were injected, a chemosis occurred, result- ing no doubt from the fact that a little fluid was extrav- asated into the sub-conjunctival tissue. Operation made May 25. 29. Intense ocular inflammation, conjunctiva of a uniform red color; cornea clouded, of a pearl gray tint; iris very red, tumefied. The animal seems to suffer much when it is examined. THE BACTERIA IN SURGICAL LESIONS. 183 30. Still much inflammation, the ear is very warm, fever intense. June 4. A capsular cataract is recognized, white, milky, and glistening. 5. Aspiration by means of Pravaz syringe. A white membrane was obtained and examined under the micro- scope. It contained a great number of pus corpuscles, a very great quantity of highly refractive yellowish bodies, resembling cryptococcus, and a small number of bacteria. 10. The inflammation is still considerable. Exp. III. — As a control experiment I made an in- jection of distilled water into the eye of a rabbit. The injection was well made, and, as in the preceding case, a chemosis occurred. June 10. There has been no reaction of any sort, either local or general, and it is impossible to distinguish the eye into which the injection was made. The inflammatory properties of the micro-organ- isms being demonstrated, we can easily understand the pathology of an abces de voisinage, and we con- ceive also the consecutive formation of new ab- cesses as a result of the first. This is one of the modes derived from a local process by which pu- rulent infection is accomplished. As a general complication, we must mention the penetration of the microbe into the blood, and the possibility, thanks to this liquid, of the infectious agent being transported to all the organs, where it will form, either centres of softening and suppura- tion, which have been called metastatic abcesses, 184 PHYSIOLOGY OF THE BACTERIA. or, by a little different mechanism, veritable em- bolisms. A very curious fact was published not long since, which supports this view. This observation is due to Hjalmar Helberg (of Christiania). In the case of a woman in whom the mucus membrane of the uterus was found to be covered with a great num- ber of micro-germs, the tissues of the eye pre- sented a series of lesions, which microscopic ex- amination showed to be due to the presence of parasites. In the cells of the cornea, in the ves- sels of the choroid and of the retina, were seen veritable plugs containing bacteria identical with the micro-organisms found in the genital parts. The author admits that the ocular inflammation had been produced by septic embolisms. I will not insist further upon the embolic pro- cess, which is studied in another chapter of this work. To sum up, I will say that, so far as the influence of bacteria on wounds themselves is concerned, we know as yet nothing positive ; since, as I have said, we find these parasites upon the surface of solutions of continuity which progress most rapidly and surely to a cure. Better informed in regard to the gener- alization of the process and the infection of the organism by products formed on the surface of the wound, we cannot dissimulate the fact that much of our information is still upon the border- line of hypothesis, and that it would be imprudent to accept it yet as invariably settled. According to all probability, we will find the key to these THE BACTERIA IN SURGICAL LESIONS. 185 obscurities when we know better how to distin- guish the different kinds of microphytes. Indeed, while Billroth only admits two invariable funda- mental types, Coccos and Bacteria, Weigert has recently expressed views quite opposed to these in speaking of the bacteria of fermentations and of chromogenes, which according to Cohn and Pas- teur constitute as many physiological species as there are different fermentations and colorations. According to Weigert, there are an infinite number of sorts of bacteria, arising from the fact that each Micrococcus assumes special vital properties ac- cording to the medium in which it finds itself, and consequently gives birth, as the result of decompo- sitions which it effects in taking possession of oxy- gen, to various chemical products acting as morbid viruses. Influence of the Preceding Notions upon Thera- peutics. — We have just shown that for many au- thors ‘germs are the origin of the greater part of the complications of wounds, it was then natural that they should seek to prevent their develop- ment. In order to attain this result, the clinicians have used means either physical or chemical. M. Alphonse Guérin, founding his practice upon the ideas of Pasteur regarding the possibility of filtering and purifying the air by passing it through cotton-wadding, conceived the idea of covering wounds with a considerable quantity of cotton, and realized—the fact cannot be denied—an immense progress in the treatment of severe traumatisms. 186 PHYSIOLOGY OF THE BACTERIA. But while the surgeon attributed his success to the absence of germs, and gave all the credit to M. Pasteur, the microscopists had no difficulty in proving that, far from being exempt from them, the pus of the wounds kept under these dressings swarmed with micro-organisms. It was, then, to some very different conditions that the real progress as realized by M. Guérin should be ascribed. The constant temperature, the absolute immobility, the continued pressure, and consequent absence of any rent of the tissues, as well as the absolute want of absorbent openings upon the surface of the wound, are probably the circumstances to which so many happy cures have been due since 1870. Among the chemical agents to which recourse is had we must place in the front rank carbolic acid, extolled especially by Lister. Not more than for M. Guérin can we deny the fact that: the number of cures after severe surgical operations has been considerably increased by operating under a cloud of pulverized carbolic acid solution, and applying upon the wound nothing but dressings which have been for a long time submitted to the action of this agent. But in this instance also the interpre- tation was a mistaken one, in seeking the secret of success in the exclusion of every microbe; for, in a great majority of cases, Virchow has not been able to find any appreciable difference between the pus treated by the old methods and that of wounds submitted to that of Lister. And, never- theless, purulent infection disappeared, complica- tions of all kinds diminished singularly in fre- THE BACTERIA IN SURGICAL LESIONS. 187 quency; and union by first intention is attempted and often obtained in very extensive wounds, where formerly it could not have been hoped for, even in the cases which presented the most favorable appearance. Let us rejoice that we can record such favorable results; and, however cloudy the present theories concerning bacteria may be, let us recognize that the labors of Pasteur and Cohn have at least had the merit of inspiring great reforms, which are subjects of just pride in the operative surgery of the present day. Many other substances have also been praised as being an obstacle to the development of germs. We will only mention the permanganate of potash, the hyposulphites, chlorine water ,and tincture of eucalyptus, of which the action is doubtful. We must still mention glycerine, which from its affinity for water has the property of fettering the move- ments of bacteria, and determining at their ex- pense a considerable exosmosis. We will not return here to the subject of the origin of micro-organisms, but refer the reader to the chapter in which this has already been treated. CONCLUSIONS. WE may sum up as follows. the actual state of our knowledge upon the bacteria : — 1. The bacteria are cellular organisms of vege- table nature. 2. Their organism is more complicated than was for a long time believed. The principal points brought to light are: their structure, the presence of cilia, the nature of the substances contained in their protoplasm, — colored granules, grains of sulphur, etc. 3. The forms of torula, zooglea, leptothrix, my- coderma, etc. 4. The multiple affinities of the bacteria, on the one hand with the alg, on the other with the fungi, differently understood by authors, and their development, still unknown for the greater num- ber of species, make it impossible to classify these beings except in a provisional manner. 5. This development, well studied in several ‘species of Bacillus, has proved that bacteria may multiply not only by fission, but also by formation of spores, and even by veritable sporangia. 6. These spores or permanent germs are the PHYSIOLOGY OF THE BACTERIA. 189 principal means by which these inferior organisms are disseminated. 7. 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